This week in Washington, there were several rooftop parties thanks to Sip With Socialites, Bitches Who Brunch and Thrillist; Colbie Caillat and Carole King partied at the Library of Congress, Rob Lowe popped into his wife's trunk show at the Quinn's, Eames Demetrios hosted a talk at Room & Board and more:

Emmy Rossum, Alden Ehrenreich, Alice Englert and more step out for the Hollywood premiere of Beautiful Creatures; the Producers and Engineers Wing host a jazz-filled Grammy Week celebration honoring Quincy Jones and Al Schmitt; Samantha Mumba, Greg Louganis and others attend the Whole Planet Foundation's Pre-Grammy Benefit concert—get the rundown on L.A.'s top Wednesday events in this installment of Last Night's Parties.

The 54th Annual Grammy Awards takes over the Staples Center; Paris Hilton and Afrojack attend EMI's Grammy after party; Tony Bennett and Diana Krall perform at Clive Davis and The Recording Academy's Pre-Grammy Gala; Ne-Yo and Compound Entertainment throw a Pre-Grammy midnight brunch; Kelly Clarkson and John Legend attend Sony Music Group's Grammy Reception at Cecconi's; Bruno Mars performs at Warner Music Group's Grammy Celebration hosted at Chateau; Jay-Z's Roc Nation holds a pre-Grammy brunch at Soho House; MusiCares honors Paul McCartney as person of the year and raises $6.5 million for artists; Cash Money Records holds their 3rd annual pre-Grammy Awards party with Lil Wayne and Drake; Flo-Rida and Pia Toscano rock the house at OK! Magazine's pre-Grammy event—Los Angeles was alive with music this weekend and we've got your inside scoop on all the festivities and the celebrities who attended them in this edition of Last Night's Parties! More»

Jean Dujardin beats George Clooney for best actor and Mary Tyler Moore receives lifetime achievement award at the 18th Annual Screen Actors Guild Awards; Sofia Vergara and Meryl Streep have fun with friends at the Weinstein Company and Dewar's post-SAG Awards cocktail party at the Chateau Marmont; Amber Heard dazzles fans on the red carpet as Kelsey Grammer hosts the 64th Annual Directors Guild of America Awards; Katy Perry and professional party girl Paris Hilton kick off the grand opening of 1 OAK Las Vegas; More»

Last night Alexander Skarsgard and Kirsten Dunst came to the screening of Melancholia, Scarlett Johansson hosted an event for Scott Stringer at the Jane Ballroom, Sarah Jessica Parker went on a treasure hunt with Andy Cohen, "Dirty Girl" screened then partied at the Jimmy and so much more! Last night's parties were all about partying for a cause. More»