Bill Irwin and David Shiner's return engagement of Fool Moon, currently playing at San Francisco's American Conservatory Theatre, is proving just as popular the second time around. An extra week of performances have been added, lasting through Aug. 19. Performances began in the Geary Theatre July 20.

In Fool Moon, Irwin plays his sweetly mischievous persona off Shiner's more astringent one. Some of their routines incorporate music by the bluegrass band Red Clay Ramblers, who also perform solo during the show. The ACT press release promises the "grand masters of physical comedy will literally climb the walls of the Geary Theatre, turn audience members into performers, wrangle with everything from microphone cords to the stage curtain...all without uttering a word." This is the second engagement of Fool Moon at ACT after the sold-out run in Sept. 3 Oct. 11, 1998.

Irwin, recipient of a MacArthur Foundation "genius" Grant, developed his silent clown persona in such shows as The Regard of Flight. He directed and starred in an Off-Broadway production of Moliere's Scapin for Roundabout Theatre Company, co-starred in Waiting for Godot at Lincoln Center, and directed A Flea in Her Ear, also for Roundabout. He is currently filming the HBO production of "The Laramie Project" and can be seen as Lou Who in the live-action "How the Grinch Stole Christmas."

Shiner made his Broadway musical debut in 2000 as the Cat in the Hat in Seussical. His past work includs clowing with the Cirque du Soleil.

Designing Fool Moon are Douglas Stein (sets), Bill Kellard (costumes), Nanacy Schertler (lighting) and Tom Morse (sound). Tickets are $61-$15. American Conservatory Theatre's Geary Theater is located at 415 Geary Street. For reservations, call (415) 749-2250. American Conservatory Theatre is on the web at www.act-sfbay.org.