Possibly the biggest con of all - KENO! Exists in various forms - Heads or Tails is a 'favourite' (for those who run it, that is, not the hapless players) in Australia. The payout odds are favourable to the house somewhere between 25% and 50%. Basically exists to snare people who are bored/inebriated/desperate in the pubs.
Not a lot better. Depending on the machine you are playing the machine will be programmed to retain up to around 10-13% of your money on average for Pokies in Australia, 2-18% for slots in Vegas - and up to a staggering 30% for some fruit machines in the UK. Pokies and slots have the allure of possible big payout and thus resembles a lottery: very likely to lose but could win big. Fruit machines...why bother?
Over time you won't win at roulette. In Australia and UK the house has an edge of 2.7% (being the zero number on the wheel) and in Vegas the house has an edge of 5.4% (a zero and a double zero).
You can win in the short term using a Martingale approach (aka double or quits) but you will reach the table maximum or the end of your funds in an amazingly short period of time.
The alternative is simply to cheat by 'past posting' (using David Copperfield-style sleight of hand to place chips or increase bets after the ball has landed) or using lasers to predict which segment of the wheel the ball will land in and betting accordingly. With the security cameras on show these days, you might last about 5 minutes - if you are lucky.
Other casino games
The games that offer the best odds are craps (0.6% edge to the house) and blackjack (0.8% edge to the house - providing you play your hands perfectly).
Blackjack is perhaps the only game where it has been possible to beat the house consistently through card counting. That is, noting the number of low cards (2 through 6) and high cards (10 through the colours to Ace) and amending the size of your bet according to the odds of being dealt a good card, sometimes known as the Kelly criterion or Kelly model. Also, where decks were poorly shuffled, it was once possible to recognise sequences.
Three problems with this: (1) if you win consistently, you get barred. (2) Shuffling is now done by machines: i.e. properly. (3) You have to play perfectly for hours for the odds of you winning to move in your favour.
The best option is not to gamble at casinos. Period!