This game is as old as the hills and a bald man called Robert Robinson has hosted a TV show with this name ever since I was very young (a long time ago, alas).
Students are put into 2 teams and are given a number of difficult but useful words. For each word they must create definitions, one of which is correct, but the others of which are complete rubbish. The word comes up and the definitions are all read solemnly out with the story behind the word, its origin etc all included if possible. The other team must decide which definition is correct.
It sounds like a rather dry exercise, but, if the students are encouraged to use humour in their definitions, examples and etymology, this can actually be a riot.