A Drunk Christina Aguilera, Matthew Morrison As Richard Simmons & More! [PHOTOS]

The celebrities were out in full force last night to celebrate Halloween. Hugh Jackman and Kate Beckinsale, with her ex-husband Michael Sheen, were out with the family, a slew of celebrities went to some grown up parties. Christina Aguilera was seemingly tipsy, Matthew Morrision embraces his inner Richard Simmons, and Lauren Conrad gave us a lame Big Bird.

Click through the gallery and let us know who you think pulled off their costume the best.