Celebs have always inspired Halloween costumes. There are the classics: Marilyn, Madonna, MJ. With the crazy looks superstars are working these days (like say, wearing a big yellow box on your head), we've got even more options. If you're looking for something  that's pretty out there, this video from celebtv.com breaks down different looks for Nicki Minaj, Ke$ha, Katy Perry, and Lady Gaga.