Marc Malkin

SWEAT SHOP: A workout-gear-wearing Katie Holmes, leaving Foresight Studios in Los Angeles. Miley Cyrus shot one of her dance-off videos there. (You know if there's a possibility we can mention Miley, we probably will!)

STYLE OF THE TIMES: Sir Elton John, cohosting the annual cocktail party for British GQ at Cecconi's in West Hollywood, with guests including Gwen Stefani, Gavin Rossdale, Josh Groban, Sharon and Kelly Osbourne, January Jones, Sarah Silverman and designer-turned-director Tom Ford.

Despite telling us that he thinks Twitter is "silly" and "dumb," John Mayer continues to use the social-messaging network. Read on to find out about his most recent party tweet.

BOYS' CLUB: John Mayer, Keanu Reeves and Mark McGrath, hitting the premiere party for Anvil! The Story of Anvil at the Dark Room in Los Angeles. Mayer even twittered a pic from the night.

CITY SLICKERS: America Ferrera, being toasted by Alexis Bledel, Vanessa Williams, Becki Newton and Patricia Field for her new Gotham magazine cover at Pranna Restaurant's Peace games VIP lounge in NYC.

TEACHER'S PET: Tom Cruise, presenting an award to Fox Film Entertainment honchos Jim Gianopulos and Tim Rothman during the annual MLA Partner Schools gala at the Beverly Hilton Hotel in Beverly Hills. Jack Black served as master of ceremonies, while will.i.am performed.

IDOL WORSHIP: Dee Snyder, cheering when American Idol alum Constantine Maroulis sang Twisted Sister's "I Wanna Rock" during the opening night performance of Broadway's Rock of Ages.

MUSCLE MEN: Justin Long, taking turns on a Nautilus machine at Equinox in West Hollywood with romance novel cover-cheese Fabio.

SIDEWAYS: Esai Morales, drinking Hennessey sidecars with a group of friends at Bar 108 in NYC.

PARTY PEEPS: Michael Phelps, with girlfriend Caroline Pal, at a VIP table next to the DJ booth at celebrity hot spot Tenjune in NYC.

SHOP HAPPY: Vanessa Hudgens, picking up a leather jacket and two sweaters at Fornarina on Melrose Avenue in L.A.

STIMULUS PACKAGE: Flo Rida, showering the audience with $10,000 in one-dollar bills during his 45-minute set at Blush Boutique Nightclub inside the Wynn in Las Vegas. Darn, why weren't we there?!?

—Additional reporting by Dahvi Shira and Claudia Rosenbaum