The Gales School, at 65 Massachusetts Avenue NE, was built in 1881 and used as a school until 1944. Since then, it's had a variety of uses, from temporary housing for returning soldiers to offices for the rent control board. In the early 2000s, it was used as a hypothermia shelter for the homeless. It's been empty for the last few years, though, and has to be held up by steel beams. The current plan is for Central Union Mission to sell its building at 14th and R Street NW and rehabilitate the decrepit shell as a shelter for men.
Over the years, the District has built and then discarded many beautiful schools. Here's a good selection of particularly historic buildings, some of which have made their way back into good use, and others that are still sitting.