Katy Perry co-hosted the 2010 Teen Choice Awards with the guys of Glee and had the costume changes to prove it. The show airs tonight at 8 p.m. on Fox. My favorite looks of the night? Katy the prom queen, Katy in a strapless, striped mini and of course just plain old Katy in a much more demure performance outfit of tights, gray shirt and black vest, definitely more tame than her California Gurls look. Enjoy!