Joel McHale, Julie Bowen, Jason Bateman and other celebrity moms and dads hit Barker Hangar for arts and crafts with their kids to support P.S. Arts; Lauren Conrad and Jaime King help Rachel Bilson celebrate the one year anniversary of ShoeMint; Adam Levine, Christina Aguilera, Cee-Lo and others celebrate season three of NBC's "The Voice"—check out who was partying where over the weekend in this installment of Last Night's Parties.