I have tried gambling with my friends when we are bored like if a red car passes by you would win,
I'm related to this kind of game. When I'm with my friends and we are on the road and nothing to do. We are betting on the color of the cars but we have some special rules to set. Like we are setting a certain period of time then we choose a color. The most car with our chosen color that passed in that period of time will be the winner. The loser(the lowest number of car color that pass through) will treat everyone.
Just a clear example that we can really gamble on everything! I remember too that I was gambling with friends with just simple child games like go fish or even UNO. Back when we were kids, I think this also is true in other countries, we play punch buggy. Whenever there is a volkswagon buggy passes and you see it first you can punch your seatmate, it's somehow gambling for punches, I guess.