The movie trailer is an underappreciated art. A good trailer (like the one for Gravity) can feel like a short film in itself. A bad trailer (like the trailer for the recent Dwayne Johnson Hercules movie) can be a tiny, festering bomb of scabrous misrepresentation and cinematic clichés. One day, there will be a trailer film festival that gives the art form its due. But tonight, SIFF is presenting a collection of the “trashiest” 35-mm trailers from its archives and serving them up with Twinkies and Cheez Whiz. That sounds like a lot of fun, too. (SIFF Film Center, Seattle Center, siff.net, 7 pm, $7)