The Spitting Game was a game invented by me and my sister when we were in elementary school. The equipment for the game were simple...two people,a cup and a supply of water, since using another fluid can be both costly and messy.
The object of the game is to make the person drinking spit out their water. This is done, by, when the drinking person is about to swallow, the other person yelling out a phrase such as "Bob Doll smokes crack" or "Hey Now, your a pr0n star" or a random stream of obscenity. This causes the person to laugh, and spit up the water instinctivly.
The problem with this is, most people won't laugh when you want them to. That is why it is important to think up totally unexpectedly things to say. It is more the surprise then the humor that will cause them to spit. That and a natural gag reflex makes people prone to spit out right before they swallow. Also, after a person has spitted once, it makes it harder for them to swallow subsequently. If the game is played enthusiastically enough, it can even transform into the vomiting game, which is not very fun.
Although this is a game, it is not actually a contest. Nobody plays it unless they want to end up spitting up on themselves. And also, while the game may not seem like that much fun, it makes its own fun. Much like Bubble Bobble, once you get over the ridiculousness of what you are doing, it is very enjoyable.