aside from poker, i don't gamble. and poker isn't really gambling. so basically i don't gamble. but last night i was out with a girl who does. we had a few drinks and she wanted to play a roulette slot machine. so i put in $20 and had a go at it. my strategy was pretty simple. i would bet $1 on either red or black. if i lost, i would double my bet until i won. after winning, i went back to betting $1. after about 20 minutes, i was up to $100 and got a couple rounds of free drinks. so i cashed out and quit. she made fun of me for betting only red or black. but the $80 covered the drinks from earlier so anyway, i just figured out the odds of winning with this system and it works out like this. with $20, you'd have to lose 5 bets in a row to go bust. the chances of doing that are only 2.7%. so i basically had a 97% chance of winning $100 with my $20 bet. the odds increase in your favor the larger your bankroll gets, as you'd have to lose more consecutive bets. the only thing is you have to be committed to doubling every time.