Even in the ultracosmopolitan East Bay, it’s difficult to find venues that are willing to book the kind of wacky, experimental-music shows that wouldn’t go over in a place like the Stork Club — shows in which you’d expect to see Tom Djll blowing into the wrong end of a trumpet, Phillip Greenlief bobbling a triplet figure over and over, or the Moe!kestra! reading from a graphically notated score. It’s even harder to find venues with a desire to make such music accessible for all ages. Enter 21 Grand, a beloved gallery and performance space that showcases some of the best avant-garde poets, authors, playwrights, experimental filmmakers, photographers, conceptual artists, and musicians from local and national underground scenes. Neither self-consciously hip nor beholden to any particular genre, 21 Grand founders Sarah Lockhart and Darren Jenkins take risks on new projects and artists who fall outside the bounds of convention. Many of the works they feature are less about finding aesthetic bliss than deconstructing the creative process. Chancy ventures, indeed, but Jenkins and Lockhart have little left to fear. Since opening their original space in 2000, they’ve already weathered two evictions. When they say they’re in it for the long haul, they really mean it.