Slacker spent a long time getting to a national audience, and there's a solid argument that that didn't even really happen until the Criterion release, but it "premiered" in 1991 at Sundance if you can call it a premiere when the film had been playing in Austin for months.
Whenever you count it as coming out, Richard Linklater kicked off the American indie movement of the 90's with Slacker and managed to craft a film that stays interesting despite its just a series of people talking to or past one another.
I didn't realize until after the episode that the UFO enthusiast was quoting at length the theory presented in Alternative 3, a 1977 BBC April Fools joke that got separated from that context due to a strike and took on a life of its own when certain people started believing it was a false-false flag -- a presentation of fact disguised as fiction. Some call it the Mercury Theatre War of the Worlds of its day, and it's a great watch as long as you don't buy into it. Whole thing's on youtube.
Also I failed to mention it in this episode, but the Old Anarchist's interactions with the thief reminded me of a Brian Zahnd piece related to his book Farewell to Mars about non-violence, though I did talk about the piece during the Straw Dogs episode.