Personally, The Rocky Horror Picture Show.
I knew it was going to be quite the experience before I went for the first time‡ but it was so much fun I had to keep going back bringing friends each time.
It’s still a fun tradition to do though we haven’t done it since last year, we’re probably going to try and go again in a few weeks.
‡ I had seen it many times before going to see it in theaters for the first time.
Inglorious Basterds. Christopher Waltz is just so good in that role.
I dunno why someone downvoted you for this one - Christoph Waltz is amazing in everything.
The glass of milk scene is one of my top two most tense scenes in all of cinema that I’ve seen. The other being the coin toss in No Country For Old Men.