The Agenda in L.A.

LOS ANGELES — From a costume party to a primer on wearing oversize T-shirts, designers and retailers here are embracing Fashion’s Night Out.

West Coast outposts of New York-based retailers such as Phillip Lim on Robertson Boulevard and Judith Ripka on Rodeo Drive are staying open late and uncorking the Champagne. As in his New York and Tokyo stores, Lim will unveil five archival pieces he has re-created with new fabrics and embellishments for fall. Ripka will hold a ring auction.

Among many activities at the Fred Segal complex on Melrose Avenue: Ron Herman will showcase one-of-a-kind necklaces by local design duo Alison Brooks and Anika Poitier of Brooks Poitier; Fallout Boy lead singer and Clandestine Industries founder Pete Wentz will show pieces from the apparel collection, and Whitley Kros designers Sophia Colma and Marissa Ribisi will show how to perfect the oversize T-shirt look.

On Crescent Height Boulevard, accessories boutique Roseark will showcase designers Mannin, K. Brunini, Deanna Hambro and Capstone Couture, along with a meet and greet with artist Robbie Conal in its gallery.

In Santa Monica, Toms shoes founder Blake Mycoskie and Trovata founder and creative director John Whitledge will team up at Toms headquarters to host a shopping and costume party in which guests are asked to come dressed as a famous family. The best dressed will win a $1,000 shopping spree.