Compete for $500 in cash prizes at the Mystic Theatre’s costume contest, which is part of its Halloween bash on Saturday, Oct. 29. Bay Area rockers the Mother Hips head the bill, which starts with Nicki Bluhm and the Gramblers at 9 p.m. at the Theatre, 23 Petaluma Blvd. N. Tickets are $25.

More information: 765-2121, mystictheatre.com.