Here's a little widget that I wrote a year and a half ago. It finally passed 20,000 downloads from the Yahoo Widget Gallery, with mostly positive reviews. It just uses one button: press it to go up, release it to go down. Note: you must have The Yahoo Widget Engine installed in order to use the Galactic Dodge widget.

Get the Widget

I had considered rewriting it as a web app, but haven't gotten around to it yet.