From its Web page:
I downloaded it and installed it on Eclipse 3.1.1 and it is promising.
It seems inspired a lot by greasemonkey and I'd like to see what kind of scripts the Eclipse community will create.
A first script I'd really like to get is to transform code comments like
//BUG 12345 into a clickable URL to our bug tracker.
A concrete example of what can be done with Eclipse Monkey is Wayne Beaton's Flickr script