What are some good fairly current (hip-hop/pop) songs i can use for a mash-up?

what are some good (hip-hop/pop) songs i can use for a mash-up? i am a kid DJ and i'm DJing my school dance. (Oh Yeah! lol) i've never done a mash-up before but yesterday i tried it (with glamorous - fergie and what goes around comes around - Justin Timberlake) and it was SO cool... i need some songs i can mash-up for my own entertainment and to play at the dance!!! TY to all of you...i wish i could pick all of you as best answer (except all who put me down or scam me)