Hey does anybody know any games for teens to play at a pool party?

ok so i need u guyz help im throwing my first pool party {im 13}...and my party is 4rm 1pm-8pm..and that is a long time so do u guyz have any suggestions for what i can do ...like games and stuff..im also gonna have water ballons..and food of course and music...i don't have a limbo set)=