Ghostzilla!

Ghostzilla!
http://www.ghostzilla.com/

Ghostzilla is a Web browser like Firefox, but it shows up and disappears instantly, discreetly, blended with your application -- any application -- so the Web pages look like part of it and not like the Web at all. (Read here how.)

What would you use it for?

1. Hide from your boss and coworkers. Not a good idea; you can get fired (the network administrator sees everything you do) or end up wasting lots of time.
2. Survive endless meetings (if you have a laptop; kind of like (1) but a little better).
3. Have a browser instantly available and dismissable within your work application, washed out from ads and unnecessary pictures. This is actually useful -- except you risk developing attention deficit disorder. Seriously.

So what's it for then?

* Entertainment. Ghostzilla is a form of computer art.