Stars' Summer Fun

Whenever Tara Reid's around, sparks are sure to fly. This time, the Taradise host lights up while hard at work Aug. 4 during a European tour for her E! travel show (formerly known as Wild On). A few days earlier, she tore up Saint-Tropez with pal Paris Hilton.

Nicky and Paris Hilton are the life of the beach party in the French Riviera, where in July they also hit the hot spots Nikki Beach, Club 55 and the V.I.P. Room. "They walked everywhere in bathing suits with a television crew and paparazzi following them everywhere they went," a source says.

Although Jessica Simpson spent much of the summer promoting her movie The Dukes of Hazzard, she lets loose in July with a mouthy pal at her 25th birthday party. "The entire night was perfect," she told PEOPLE after the bash held at her parents' house. "I'm still smiling."

Sand too hot for bare feet? Nicole Richie gets a lift from her personal strongman, fiancé Adam "DJ A.M." Goldstein, in July. A week earlier, they celebrated their engagement with a star-studded bash at the home of Richie's dad, Lionel.

Between promoting Herbie: Fully Loaded in the States and Europe, filming A Prairie Home Companion in Minnesota and supporting her mom during her divorce trial in New York, Lindsay Lohan finds time to take a spin on the turntables with deejay pal Samantha Ronson at Teen People's Young Hollywood party on Aug. 13.

Jeremy Piven bangs on the bongos during a fete for his Hamptons magazine cover at Manhattan club Cain on Aug. 23. The single Entourage star then made his way over to a party at Marquee, where he grooved to someone else's beats with costar Kevin Connolly.

Colin Farrell cozies up with some pals and brother Eammon (right) for a marathon night – he was spotting leaving hot spot Mansion at 6 a.m. – in June. But it's work that has the actor in Florida: He's been filming the big-screen adaptation of the '80s TV classic Miami Vice with Jamie Foxx.

A newly svelte Jack Osbourne has a swinging good time Aug. 6 at Urban X, part of a three-day extreme-sports event where world-class climbers scaled tall buildings in an (almost) single bound. "I feel bulletproof," Osbourne recently told PEOPLE of his newfound passion for climbing.

The party doesn't stop at 40: Brooke Shields and best friend Juliette Hohnen ring in their fourth decades during a joint birthday bash Aug. 13 at the Brentwood Restaurant and Lounge. Joining the ladies for dining, drinking and an impromptu conga line were their husbands, Chris Henchy (with Shields) and Steven Weber, and pals Ben Stiller, Christine Taylor, Kevin Nealon and Jim Belushi.

Still crazy in love after all these years, Beyoncé and Jay-Z play on the streets of Portofino before boarding a private yacht to set sail for the French Riviera in June. The couple, who have been dating for three years, wrapped up their high-seas adventure in Saint-Tropez.