Jeanne's arbitrary rules idea is great. I do this with word count often, seeing how a scene would change if I forced it down by half or whatever. Or one of my favorite, change the feel of the scene. If I have a sunny day, I re-write the scene with pouring rain and see what that does. Fun stuff even if you don't use it, it keeps your thinking less limited.

I know re-writing a scene if frowned upon by some, but I've benefited the most in editing when I'm standing over my editor's shoulder (when a newspaper reporter) and watching him/her slash and change. I know you will come up with better ways to incorporate everyone's comments. You know your characters, what they think, what the room smells like, what you want to foreshadow and underscore. Sure use what you will, but know that what you write will always be better.

Oh and another fun one is to give a character in a scene something to be preoccupied by -- late to pick the kids up from school, worried her underwear line shows, replaying fight with wife. I love adding that because it gives another layer easily, forcing scenes to do double or tripple duty. Have fun with it.