The Marsh and its adjoining Mock Cafe regularly host works in progress, workshops, and kids' stuff as well, and there will be some of each at "The Marsh 10th Anniversary Festival and Carnival." The festival begins at 3 p.m. Friday with the Sparrow Brigade, a parade of electric cars and motorcycles, and Zappys, electric skateboards and scooters (free), followed at 7 p.m. by the Marsh All-Star Gala Benefit, where Varon and Kornbluth perform with clown Jeff Raz and juggling storyteller Sara Felder -- local eateries provide refreshments and Gunnar Madsen plays waltzes at a post-show dessert-dance ($100). The Community Carnival features a pet parade and activities for all ages, although performers will especially enjoy "Fish for Funding" and "Knock the 'Little Man' Off the Chair" as well as tips on circus arts, costuming, and makeup. It begins at 1 p.m. Saturday ($5-10), followed at 8:30 p.m. by the All-Star Performance with J. Raoul Brody, Ian Shoales/Merle Kessler, and many others ($15-20). All events take place at the Marsh, 1062 Valencia (at 22nd Street), S.F. Call 826-5750 for more information.