starring Simon Pegg, Nick Frost, and the voice of Seth Rogen.
Clive and Graeme are best friends and artistic collaborators--Clive is a writer, Graeme an artist--who travel from their home in England to the San Diego Comic Con, and then set out to make the most of their trip to America by renting an RV and touring the famous UFO sites of the southwest, going by the Black Mailbox and Area 51 and finishing up at Roswell. This plan quickly goes awry as they witness a car wreck, only to find that the driver is a foul-mouthed, genre-savvy alien, who introduces himself as Paul and says he needs their help to get back to the spot where his spaceship originally crashed and where his people are due to pick him up.
Pegg and Frost wrote the movie as well as starring in it, and the geek references fly by thick and fast. Both Clive and Graeme are evidently fluent in Klingon--only Clive is shown to speak it, but when he gives Graeme an instruction in that language, Graeme promptly obeys. Star Wars, Aliens, E.T., The X-Files all get their shout-outs. For somebody who's seen all that stuff, this movie is hysterically funny. I'm not sure how well it would play for somebody who would miss all the references, but fortunately I'm not in that position.