You know those silly little bets we made as kids, like I bet you can't climb that tree! It was never really about money or anything, just bragging rights.  As adults though, it gets more complicated when the stakes are higher and  even if you're just joking around.

Like say you get caught up in the moment watching a game with your buddy.  You bet your whole salary on something crazy happening - not thinking he'll actually hold you to it if you lose! But legally, could he make you pay up? Im guessing it depends on your local laws and the specifics and all.

Anyway, my advice is to keep it light with bets.  Don't let things escalate too far just because you're feeling cocky.  Otherwise you might end up learning the hard way where that legal line in the sand is drawn!