What song should I sing for a high school talent show?

Well, I know school hasn't started yet, but I'm going to be a
freshman, and the talent show is like, your whole social status in the
high school I'm going to... So, that said, what can I sing? I play
piano, so it would have to be a song I can do on the piano.. I rap
too.. I just don't know what I could sing that the crowd would enjoy
and everyone will know.. Something recent..
Any ideas??