1985, dir. Martin Scorsese. Griffin Dunne plays a nebbishy NY office worker with a dull life. And insomnia. Decides to go out to a Soho diner and have coffee late one night. Meets increasingly odd people, and gets entangled in their lives. And by "entangled", I mean "cannot escape Soho and go home (or sleep)". I think it isn't too much of a spoiler to say that it ends at dawn.

I guess I would categorize it as a dark comedy. It's the sort of film that can make an ice cream truck scary.