Teeth!

Teeth is a great game because you can play it anywhere, you don't need any materials to play and it's bound to make people laugh!

To start with, everyone chooses a vegetable to be their name; odd sounding ones are best. Say them out loud a few times so everyone remembers who's who.

Play goes from player to play by repeating your own vegetable name twice, then another player's vegetable name twice. The other player would then say their vegetable name twice, then the vegetable name of another player, like this.

Artichoke: Artichoke artichoke, sprouts sprouts!
Sprouts: Sprouts sprouts, carrot carrot!
Carrot: Carrot carrot, cucumber cucumber!

... and so on. The game is made difficult (and fun) because players aren't allowed to show their teeth at all, so have to speak with their lips covering their teeth at all times. If someone makes a mistake (not noticing that it's their turn, or forgetting the names of other players left in the game) or shows their teeth at all, the other players put their hands behind their head and flap their elbows about shouting "Teeth! Teeth!" The person would then be out of the game.

Obviously, players aren't allowed to cover or hide their mouth at all, because that wouldn't be as fun.