Paris Hilton and David Arquette celebrate the launch of a new male modeling agency at Bootsy Bellows; Maria Shriver helps honor Rob Lowe with the Anti-Defamation League at the Beverly Hilton; Lucy Hale, Tyler Blackburn and the cast of "Pretty Little Liars" hit a special screening of their Halloween episode in the Hollywood Forever Cemetery—we have the rundown on Tuesday's top events around town in this installment of Last Night's Parties.