Everybody should know so much about George Washington that these twenty-five facts should be old hat. Chances are, though, you don’t know the majority of these. For example, what is G-Dub’s middle name?

And no, writes author David Plotz, this exhibit has nothing to do with the politics going on there. Here’s how he describes it: Ellen Harvey’s “The Alien’s Guide to the Ruins of Washington, D.C.,” on display at the private Corcoran Gallery of Art until Sunday, is an exhibition that takes place in the future, after …