The only gambling I do is I play this horribly offensive game with a couple of my friends. We see an attractive lass, we point her out to the other person(s) who are playing the game. We take turns and select one of the girl's "features" that we like the best and the other person has to guess what that feature is. Guess correctly you win a dollar, guess incorrectly you pay the person a dollar. Really the game is about how well you know your friends preferences for women.
For the sake of discretion and brevity we have shortened the choices to letters that represent words. I'm sure you can guess them: a, b, f, l and if it's not one of those you just say it. We've had choices be disputed, but it's a gentleman's game so we trust each other to play fair and not pick something obscure and impossible to guess or change their choice after the other player(s) guess. I guess that problem could be solved by writing it down so you can't change it but we don't do that.
We have a few rules: everyone has to be sitting down to play, the girl can't be someone that either of us know, and we try not to do the same girl twice.
It's misogynistic, crass, and probably pretty pathetic but it's fun and sometimes you win a dollar.