Birthday Help!

Hey everybody! im havin my 13th birthday on sept 11...its co-ed and about 30-45 people
I have no idea what to do...my last co-ed party was great but some of the time we just sat around or were screaming at eachother trying to start a game or somthing...i dont know if i should have a theme or what...WE ARE MATURE FOR OUR AGE!!...NO KIDDIE GAMES...PLUS WE WILL HAVE PARENTS THERE SO NO TOUCHY OR FELLY GAMES!!...I have a pool and a huge yard and also nice neighbors that let us play in their yards so...please help...either here...or my e-mail is devorich132010@yahoo.com...and my screen name is devorich132010