Big Trouble in Little China: The elevator scene in which everyone is buzzed from the cocktail they just drank. They are all happy and their is alot going on in the background during that scene.
Weird Science: Gary and Wyatt are in the bathroom. The girls knock on the door and ask them what they are doing there. Wyatt replies unseen in the background, "Gary was just taking a shit." The door closes and you see Gary slapping Wyatt with a huge smirk on his face. Makes me laugh everytime.
Revenge of the Nerds 1 & 2: I'm a huge fan of the musical numbers.
Green Mile: When they are preparing Michael Clarke Duncan's character for the electric chair. A very sad scene.
Rocky: The montages of course!
Fast and the Furious Tokyo Drift: Okay, okay, I know it's a horrible movie... but the scene where they drive into the parking ramp for the first time. All those hot asian women in small outfits. How can you not enjoy that?
Rosencrantz & Guildenstern Are Dead: The part where they are playing questions. The banter and timing is great.
There are many more but this is what I can immediately think of... who's next?