How do I jokerise a party?

Ok, it's this friend of mines 17th birthday party, and it's going to be a surprise. He LOVES the dark knight and especially Heath Ledgers joker so i've decided that i'll jokerise the party. So what I'll do is paint joker faces on the balloons etc etc. I would like the games to be joker themed too though, so things like murder in the dark and the card stacking game. Could you tell me some other games that could be jokerised and how?