Riley Giles and Lindsay Lohan Photo by: Crollalanza / Beiny / WENN
Lindsay & Riley: Hanging Tight in L.A. | Lindsay Lohan
Lindsay Lohan, staying hands-on with her new beau Riley Giles during a day out in Los Angeles. The actress has been keeping a low profile as she quietly continues working on her new movie, Dare to Love Me.

Ashton Kutcher and Demi Moore, sharing a morning hike on Runyon Canyon with a gaggle of dogs and dog walker in tow. As for their fitness fashion, Moore opted for a black tank top and gold aviators, while Kutcher sported red plastic shades and athletic shorts. Dressed to beat the heat, the only thing the happy couple had to contend with was their dogs' speedy downhill pace.

Marcia Gay Harden, celebrating the premiere of her movie Rails & Ties with a party at the Hedges Inn in East Hampton. After a screening at the East Hampton UA Theater, the actress downed a bottle of champagne at the bash with six guests (including director Alison Eastwood).

Matthew Perry, doing a boxing workout with a trainer at West Hollywood's Muscle Under Fitness. According to a fellow gym-goer, the former Friend (and aspiring pugilist?) was "looking good – really good."

Pete Wentz and Ashlee Simpson
Caught in the Act!| Caught in the Act, Lindsay Lohan, Ashlee Simpson, Pete Wentz
Ashlee Simpson, dancing as boyfriend Pete Wentz requested songs – including "Homecoming" by Kanye West – from the deejay at Chicago nightspot Manor. A Windy City native, Wentz was at the club in an official capacity, too –hosting a benefit for Invisible Children (which provides educational tools for Ugandan children). When he wasn't on the dancefloor, Wentz sipped champagne (and cuddled) with Simpson in a back booth.

Paul Rudd, forming a comedy dream team with Will Arnett (Arrested Development) and Janeane Garofalo at West Hollywood's Chateau Marmont. No surprise, but the group roared with laughter, chatting at their patio table. Meanwhile, Rebecca Gayheart shared a quiet ladies night with a female friend. Seemingly oblivious to anyone on the patio – despite the bevy of comedians – the actress and her pal shared water, some wine and even a few giggles. Also there: stylist to the stars Rachel Zoe.

• By MAUREEN HARRINGTON, KIM PEIFFER, JEFFREY SLONIM and ABBY STERN

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