It’s Nevada DMV form OBL326; so far, I’ve only heard of licenses being given to Google (May 7, 2012), but I imagine there might be others by now as well. I don’t know of any gag license requests, aimed at just getting something to put on one’s wall, but I do think a special bonus should be given to anyone who asks for a license in the name of a company called Skynet (of course, without any perjury on the application).