Now's the time on Sprockets when we say ... what the fuck? Flimsy terms such as experimental and avant-garde can't begin to pin down the calculated cacophony -- musical and emotional -- wrought by this traveling doomsday sideshow. Indeed, even describing Sleepytime Gorilla Museum in a conventional, representational language like English feels like an affront to Sleepytime's arch, Dadaist ethos. Musically, the Bay Area five-piece favors unusual instrumentation and arrangements, conjuring everything from discordant, haunted-house soundscapes to death metal. But to adapt a phrase, these performance artists are really meant to be seen and not heard. The group's stage presence is the bulk of its appeal. Its gothic, 19th-century aesthetic recalls illustrator Edward Gorey, and its surrealist stage show takes a page out of the Residents' book. But even if you're not apeshit about Sleepytime's "music," you may want to approach the stage just to make sure you're not hallucinating -- or having a nightmare.