Ke$ha Lets Loose in Chicago

 

Ke$ha drinking a Grey Goose cocktail in the private party room at Chicago's Sunda restaurant.

Penn Badgley celebrating his girlfriend Blake Lively's birthday over champagne at CV in NYC.

Neil Patrick Harris wearing V-MODA Crossfade LP Headphones at the Montage in Beverly Hills.

— Newlyweds Stephen Moyer and Anna Paquin picking up the Scrabble Flash game in L.A. — they said the kids would love it!

Amber Lancaster grabbing several pairs of Shoedazzle heels at the Reality Cares Giving Lounge in L.A.

— Cobra Starship's Gabe Saporta hopping into the DJ booth at the Eldridge in NYC to spin alongside the group Silver Medallion.

Frankie Delgado and Stephanie Pratt hanging out with Maxim's Hometown Hotties finalists at Float in The Hard Rock Hotel San Diego.

Hayden Panettiere receiving a 21st birthday gift of sweatshirts and sweatpants from Kings of Cole at the Marcel Hotel in NYC.

— Close pals Serena Williams and Russell Simmons toasting each other at the Hamptons Magazine and Pranna chef launch party in NYC.

Kevin Spacey drinking white grapefruit cosmopolitans with a friend at Gladstone's in Malibu.

— Tennis pro Caroline Wozniacki celebrating amongst fans and friends at the U.S Open kick-off celebration at LexBar in NYC.

Rick Fox sporting blue fairy wings that his daughter picked out for him at the premiere of Disney's Tinker Bell and the Great Fairy Rescue in L.A.

Quentin Tarantino, Riley Keough and James Blunt partying it up at John Terzian and Brian Toll's Las Palmas Lounge in Hollywood.

Iyaz performing for a packed crowd at Webster Hall in NYC.

Jessica Szohr sipping Svedka vodka cocktails with beau Ed Westwick at the Nylon magazine party in NYC.

Reggie Bush celebrating the Saints 36-21 victory over the San Diego Chargers at Whiskey Blue in New Orleans.

Katy Perry and Russell Brand gazing out the window at the Gansevoort Park Avenue in NYC.

John Legend engaging in a little PDA with his model girlfriend Christine Teigen by South Gate Restaurant's booth during the BNP Paribas "Taste Of Tennis" at the W hotel in NYC.

Will Smith and wife Jada Pinkett-Smith enjoying a romantic dinner at Megu New York before heading to see their son Jaden join Justin Bieber on stage at the Prudential Center in Newark, NJ.

Billy Joel dropping by Todd English's 50th birthday bash at The Summer House in Nantucket, MA.

Ali Fedotowsky and Roberto Martinez getting asked about baby plans while checking out a UPPAbaby stroller in the HBO Luxury Lounge at the Emmys in L.A., to which Fedotowsky gushed, "We were just talking about babies!"

Adrienne Bailon hanging out at Lucky Strikes for Sean Garrett's Inkwell mix tape release in NYC.

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!

Want stories like these delivered straight to your phone? Download the Us Weekly iPhone app now!