After years of being called a poster child for everything that's wrong with open source, the Mozilla project has generated some success since the release of 1.0, arguably opening up the world of web browsing again.
One of the strangest offshoots I've come across is Ghostzilla which enables you to conjure up a browser (using a special mouse movement) in your current application, regardless of what it is.
It's a little hard to explain, but there are animated screenshots on the web site which explain much better than I can.
