Busy Philipps, Ellen Pompeo and other famous mothers give mom-to-be Anna Paquin a taste of what new parent life is like at a Saturday Luau event; Kelly Osbourne, Katherine Jenkins and other transplants from across the pond honor Piers Morgan with a BritWeek celebration; Julie Bowen, Lisa Kudrow and more hit the P.S. Arts Los Angeles Modernism opening night gala; Kim Kardashian steps out in support of Generosity Water—see what else celebrities were up to this weekend when they weren't partying for Cinco de Mayo in this installment of Last Night's Parties. More»