Here are my "cures" for writer's block. I actually have to do this for a living.. so leaving stuff for extended periods is not usually an option...

1) Read something beautiful. It will start the words fitting together in your head.
2) Don't try to make it good. Editing is easier than writing, so once you get it down, you can fix it tomorrow.
3) Take a bath. Go for a walk. Take a BRIEF break. The way around the structural problem will probably present itself. Then repeat steps 1 and 2.

Allie