Sorry, I just had to post when I saw this thread to clear a few things up. Unfortunately, there are a lot of misconceptions when it comes to gambling out there, as everyone tends to view their (extremely) small sample size as gospel, when in reality, people who are making losing bets can win (and delude themselves into thinking they are winners) for a long time before the long-run catches up with them and vice-versa (winners can lose for a long time before they start winning).
To try and prevent this post from becoming it's own book, I will try to keep it fairly short. If I miss any type of game or anyone has any questions I would be glad to expand, but a little about me, I have worked on and off as both a computer programmer and professional gambler for the last 10+ years. I have been switching between the two as I get bored with one I focus on the other for awhile. Now that I found this site I am focused on building a sustainable dividend portfolio that I should be able to live off of forever, but unfortunately for me, I am not extreme enough so that is probably 10-15 years away.
Anyways, here goes:
PART 1: Casino games you can WIN at:
1. Poker: Poker has one of the best combinations of skill and luck -- by that I mean, the losers (fish) get lucky enough, often enough that they keep coming back. It's not a game like Magic the Gathering where the losers will realize they are out-matched and give up rather quickly. This will keep them coming back with more and more money for the sharks to win, although the sharks lose often enough too that it is by no means smooth-sailing. The swings (as is true in all forms of gambling) can be absolutely atrocious, and will take their toll on even the best of players. If you do not have a proper bankroll and manage it correctly you will go broke at some point (this is another topic that I could write a book about).
The casino still makes money at poker because they will take a little bit of money out of every pot or tournament entry (the rake), so based on that alone there will be more losers than winners at poker, your skill needs to be good enough to not just beat the other players, but overcome the rake as well. As mentioned earlier in this thread forumserver.twoplustwo.com is a good site for learning more about poker. People can make a living at poker playing both online and/or live.
2. Blackjack. If only I knew what I knew now but was born 30 years earlier.... (but then again, I would not want to be old right now, LOL)...
Blackjack has a very small house edge (around 1%) when playing what is known as basic strategy -- this is a chart that tells you how you should play every hand based on what your hand is and what the dealers upcard is. As mentioned previously in this thread, http://www.wizardofodds.com is a great site for calculating odds, not just for blackjack but every form of gambling.
The way to beat blackjack is by counting cards. There are a lot of card counting systems out there, but one of the most popular is the blackjack hi-lo system, as it is one of the easiest (and effective) strategies out there. Counting takes practice but is not nearly as hard as the media or hollywood makes it out to be. You don't need to be rainman and keep track of every card -- you are basically just keeping track off if there is an imbalance of ten's (Ten, Jack, Queen, King, Ace) left in the deck or not and raising/lowering your bets accordingly. The more tens left in the deck the better your edge.
By counting cards you can gain an edge against the casino -- I'd estimate it around 2-3% although you need to be careful, as unlike poker, when you win at blackjack you are taking the casino's money, not other player's money, and the casino does not like that. If you bet too much (or win too much) the casino will give you heat. Again, this is not like Hollywood makes it out to be. You won't get beat up or anything, but they can ban you from their property and you will be charged with trespassing if you come back again. So it becomes a game of cat and mouse (or hit and run) where you try to win as much as you can without setting off any alarms. So while you obviously want to win as much as you can, you cannot get to greedy (and even have to make the wrong play every now and then as cover), to assure that you will still be able to find a casino that is willing to deal to you tomorrow.
3. Video Poker: Although beatable video poker machines are becoming less and less common, similar to blackjack, every combination of cards you are dealt has an ideal strategy. Video poker machines are truly random -- by that I mean all 52 cards in the deck have an equal chance of coming up (well as random as you can get with computer programming -- again another topic), it is not like slot machines that are rigged, so this comes down to a game based purely on math, and your exact expected rate of return can be calculated on the spot by looking at the payout table (for example -- some machines pay 8:1 for a full house, while others pay 9:1, even though the chances of getting a full house are exactly the same on each machine -- obviously, you want to play on the machines that pay 9:1). The best video poker machines are called "full-pay" machines.
4. Sports betting. You need to win about 55% of your sports bets to break even, as the house takes about and extra 10% when you lose. The best sports betters win around 60%. Sometimes you can find arbitrage situations between different casinos where you can bet different sides/spreads and guaranteed yourself a profit -- but these opportunities are not nearly as good as the once were. This basically comes down to your handicapping ability. Note that Las Vegas pays the top handicappers (that they know of) a lot of money to set these lines. The chances that you are smarter than them is slim. However, they also take public perception into consideration so sometimes the true line (what they think it should be) is not the same as the line they post to the public. The casino's goal is to to get 50-50 action on each side of the bet to guarantee a profit -- as funny as it sounds -- the casino's are not in the business of gambling. If you are good enough at handicapping against the point spread you can put your money where your mouth is and hopefully come out ahead. Be prepared for lots of last second plays that cost you a lot of money.
5. Horse/Dog racing: I'll keep this short since I don't know much about it, and the house takes a large cut (often around 25%) that might just be too much to overcome. However, all players bets are pooled together before the house takes their cut, so like poker, when you win, you are actually winning other player's money not the houses (again, the casino is not in the business of gambling), but unlike poker the house is taking a much bigger cut here that is much harder to overcome.
In theory, if you really get to know the horses/dogs involved in each race, and study them, and watch them train etc... in theory you can get an edge. I'd say this is the hardest method to making a living, but also the one I know the least about it. Maybe you can include Nascar or something. I know nothing about that and probably won't soon either. Good luck if you venture down this road and I would be interested in hearing any of your stories.
6. Others??? Can't think of any right now but it is late. I will update if I think of any or anyone else brings one to my attention.
PART 2: Casino games you WILL LOSE at:
1. Slot machines: These are computer programs designed to take an exact percentage of your money. In the long-run, you will lose exactly this percentage to the casino. It varies from machine to machine, and casino to casino, but you can expect to lose anywhere from 1%-20%+ of your money when playing slots. The best slots are in areas like Las Vegas where competition forces them to give more money back to the winners, but even there you will lose everything you have if you play them long enough. The city was not built on winners.
2. Roulette. Every single bet at Roulette, whether it pays 1:1 (Red/Black) or 35:1 (a single number) or anything in between has the exact same house edge: around 6% (I would need to look up the exact number). This game is absolutely unbeatable, and no matter what you think you come up with for a betting strategy, you will lose the same exact amount of money (on average, 6% of what you bet over the long-run).
Unfortunately, if you are new to roulette and think I am wrong, well, you are just going to have to learn the hard way.
3. All other table games (except craps see below) and Bingo/Keno:
These games aren't beatable either. Go to wizardofodds.com for exact odds if you are curious for a specific game. Also, any new games that are invented have statisticians doing studies to make sure the casino never creates another game that is beatable (like blackjack). It is best to just avoid them.
4. Did I leave anything out? I don't play losing games so there is probably a lot out there that I just ignore.
Part 3: Games that *MIGHT* be beatable:
1. Craps: I am hesitant to put this here as I don't want to mislead anyone. This probably should belong in the losers section. However, when limiting your bets to just the pass line (or don't pass line) plus taking odds, the house edge is so small that, in theory, you could beat the game by dice setting. By this, I do not mean cheating. By this, I mean picking up the dice in the exact same way (the casino allows you to do this) and then throwing them the exact same way every single time. In theory, if you did this, you should be able to have certain numbers come up more often than others to offset the small house edge. This is something I am interested in learning more about but do not have any knowledge to pass on. Sorry. Unless you can create a statistically sound study in your basement, I would not suggest trying to win money with this method.
One thing to note on all of these games (mainly the winning ones or slightly negative ones) is that once you include comps, that can add significantly to your profit margin, or at least make your vacations "free" in that your hotel/airfare/food/beverage can all be included as long as you put in enough play, and if you figure out the math -- you are breaking even or coming out ahead. Obviously comps while you are playing a game you win at is just gravy. But comps can turn a slightly negative game (such as craps or a slightly negative video poker machine) into an overall positive gain if you include the comp value -- but obviously do not rely on comps, just count them as a bonus when you get them. As far as comps go (in winning games), video poker would be your best bet, followed by blackjack. Poker and sports betting are minimal at best. In the losing games, you can expect around 25-30% of your expected loss to be comped back to you, so you won't be able to come out ahead here -- except in rare situations where you are playing better than the average player (such as on a slightly losing video poker machine) where the casino comps you at the rate the average player loses at while you play better than the average player. You can also sometimes increase your comps in games like blackjack by doing tricks like sneaking chips off the table (then buying back in with cash) to make it look like you are losing more than you really are, or by betting more when the pit boss is watching and less when he is not so they think you are more of a high roller, but as surveillance/computers are greatly improving (and getting scary-good) these tricks are quickly becoming a thing of the past.
Also one last word of warning, while this might seem appealing, it is not an easy life. The saying that poker (or any form of gambling) is a great part-time job but a terrible full-time job is completely true for 99%+ of the population. It stops being fun and becomes work real quick -- and once most people reach that point they would rather have a regular job+benefits again. However, as a side-income/hobby it definitely beats most part-time jobs out there.
Also one more thing I did not discuss is progressive jackpots. In theory you could play slot machines once the progressive jackpot reaches a certain point and make money -- but since you do not know the exact odds this is tough to figure out. In Video Poker with progressive jackpots you can figure out the exact odds on the spot and start playing when the machine will be profitable.
The best thing about gambling is that you can figure out almost everything with math and/or statistics. It's a beautiful thing. If you think you can win but the math says you cannot, then guess what, the math is right and you are wrong.
A gamblers anonymous/degenerate warning: If you won money the first time you were in a casino, you are at a much higher risk of becoming addicted. I do not know the exact psychology behind this, but basically, you went into an environment where you were supposed to lose and you defied the odds and won and came out a hero. You now think you are Rainman even though a good percentage of gamblers will win their first time (or even first few times) based purely on luck. Unfortunately, this can easily go to your head if you are not careful. Keep things in perspective and do the math.
Sorry if I got too long-winded in this post!