Trivia: You may have noticed that the man who tries to pull a gun during the opening bank robbery and is later killed out of mercy by Mal looks familiar. It is none other than Glenn Howerton, best known for playing Dennis on the dark comedy series "It's Always Sunny in Philadelphia." This movie was released just a few weeks after "Always Sunny" first premiered.
Suggested correction: I honestly have no clue why I thought this counted as trivia when I submitted it, but looking back, I think it's a bit of a stretch and probably shouldn't be listed. Maybe if it was his first role it would be trivia, but it wasn't.
I'm OK with it, to be honest - might not be his first role, but I didn't know he was in Serenity, and reading this made me go back and rewatch the scene. It's a grey area, granted, but to my mind trivia encompasses anything that makes you go "huh, didn't know that"!
Definitely trivia! Super cool fact I didn't know. He is very famous Now and the proximity of the episodes in similes are definitely relevant.