For five years, some of the area's most interesting theater took place on a small, square stage above the galleries at the Boulder Museum of Contemporary Art, courtesy of Brandi Mathis, artistic director for the space. There was Eric Bogosian skewering the zeitgeist, singer-actress Ethelyn Friend singing Songs My Grandmother Taught Me, Nancy Cranbourne kvetching about menopause, the subversive performance art of Michelle Ellsworth and the first ever Colorado performance of a work by Suzan-Lori Parks. Almost every performance found the place filled to overflowing. Mathis left her post last spring, a few months after directorship of the museum was taken over by Penny Barnow and Joan Markowitz. No one is saying why.