Louise Roe, Mischa Barton, Terri Seymour, and a heap of other celebs came out to the launch of The 7th Annual BritWeek Festival; Marissa Kraxberger, Julie Bowen, and others step out to celebrate Oscar de la Renta's "Sophie Dress" with author Kelly Florio Kasouf; Dana Carvey, Mike Myers, and Lorne Michaels hit the "Party time! Excellent!" reunion for Wayne's World; Felicity Huffman, Cloris Leachman, Nancy O'Dell and other stars walk the red carpet for the 56th Annual Genii Awards; David Arquette, Shiva Rose, and more celebrate Balthazar Getty's record release at Bootsy Bellows—get the lowdown on Tuesday's top L.A. events in this installment of Last Night's Parties.