Katy Perry has been carrying even more back-straining weight than usual this summer, with the release of her documentary PART OF ME and all the promotional traveling that went along with it. Finally, she can get down to some partying and make some memories like in that "Last Friday Night" video. She's not keeping away from any large crowds as you can see here at this "'90's For A Jammin' Roller Party" for Johnny Wujek (Dancing With The Stars). Amber Heard was also in attendance, but it looks like she was the wallflower of the evening, texting her lover Depp in front of the quarter toy-machines. Katy, on the other hand, lived it up on the skating room floor, sporting a backpack filled with Beanie Babies spilling out behind her. Way to be the life of the party as usual, Katy! Hey, so can you attend my clothing-not-optional Mud Wrestle Mania birthday party next week?