I like quirky, one-off games that require a bit of adventurous investment from willing groups. Like Og: The Roleplaying Game of Caveman Miscommunication.
The short of it: you're a caveman and you're trying, along with your cavebuddies, to survive the hazards of the world B.C. (and not that shitty newspaper strip where it's B.C. but somehow Jesus already existed and died).
The catch is that you're not very smart. Caveman society, as a whole, knows only 18 words: You, Me, Rock, Water, Fire, Stick, Hairy, Bang, Sleep, Smelly, Small, Big, Cave, Food, Thing, Shiny, Go, Verisimilitude.
While the GM may describe things and you can describe actions, you can only communicate with your co-players In Character with these words and, being the caveman that you are, you only know maybe five or six. What's the difference between Hairy Thing (dog) and Hairy Thing (sabre-toothed cat)?
Depends on how good you are at mime, mimicry, and cave drawing. And, as the book says, "When in doubt, say your few words louder. That always helps."