A while back I wrote a small program named fast-live-reload. The point of it was to be able to do things whenever files change (be that refreshing browsers, or executing programs, such as Compass compilation).
Here is another sample on how I use it to try out python snippets really fast:
I basically split my current view in two (using byobu), and I edit in the left view with my trusty vim. Whenever I save, fast-live-reload picks it up and executes the script.
Instant feedback is instant ;-).