Mbari Art Gallery. 5319 Potomac Ave., N.W. Open Sundays, 1 to 6 p.m., and by appointment. 244-6094, 279-7166 or 362-2239. This is "Summertime," a mohair tapestry hand-woven at one of a burgeoning number of craft workshops in the southern African country of Lesotho. What used to be cottage industries there have, in many cases, been channeled into structured workshops where craftsmen practice their crafts for export. This tapestry has found its way into a collection of arts and crafts at an interesting new gallery named the Mbari Art Gallery. Translated from Ibo, mbari means "continuation of creativity," a goal the gallery's partners, Mimi Wolford, Linda Jacobsen and Pearl Siegel, are hoping to achieve by introducing collectors to the talent of native artisans of African and Indonesia -- in a way, it's continuation here of the creativity begun there. Tapestries such as "Summertime" dot the walls of the gallery, the first floor of a house, along with paintings of self-taught African artists. There's also a variety of hand-woven, naturally dyed Indonesian textiles that were originally worn as clothes but are now prized for their exquisite patterns and handowrk, and so are hung as tapestries. Jewelry, contemporary textiles, sculptures, baskets and prints complete the collection.