3068 Mt. Pleasant St. NW, the soon-to-be location for the Mt. Pleasant Temporium. Photo by Pat Padua. Early next year D.C. will get its second Temporium, a pop-up arts space, this time in Mt. Pleasant. The D.C. Office of Planning awarded a $15,000 grant as part of its Temporary Urbanism Initiative to “transform vacant storefronts or spaces into a unique temporary retail shop for local entrepreneurs to exhibit and sell their work.” The first…