Though Medicine Cabinet, a project space housed in a Bridgeport bathroom, is on hiatus, “alternative” galleries—many only slightly less bizarre—thrive in Chicago, and have for several years. Often run by artists, these galleries range from extra bedrooms one noise complaint away from a police shutdown to legitimate live/work spaces. While their missions differ, these venues tend to support avant-garde art that’s harder to sell than conventional gallery fare—and several were founded by students…