Get some friends together and hold a poker night. You'll need a deck of cards, some kind of currency for betting (poker chips, matchsticks, coins, etc), a couple of arbitrary markers (for the dealer/blind), some dips/snacks, and possibly some alcohol (OK, definitely some alcohol).

There are different variations on the game, but the most popular at the moment (and an easy one to get to grips with) is Texas hold 'em:

http://en.wikipedia.org/wiki/Texas_hold_'em#Rules

Don't take it too seriously, or make the bets too large (at least, to begin with...).