I don't really believe in classic writer's block. I do believe in situations where I've written myself into a corner and I'm unsure of where to go. When that happens, I'll start a short story or take a break all together and read a new book by a favorite author or one from a new author that I haven't tried.
Another good way to resolve a scene is to sleep on it. I find a good night's sleep will produce dreams with the answers I was looking for.