Lollapalooza Lineup-- what should I check out/study up on?

[Black]

The UnDoug wrote:
Outkast
Calvin Harris
Nas
Fitz & The Tantrums**
GROUPLOVE
Kings of Leon
Trombone Shorty
Delta Rae

I didn't * Kings of Leon because I just saw them..... dependiong on who's against them I may see them again.... would try to learn some of their older stuff to sing along to (I know the newer stuff inside-out.)