[Vexs]

Defraggler is the only one I can think of off the top of my head. I love that kind of interactivity in applications, so much better than a loading bar.

[digi_owl]

My first thought as well, but apparently there is another one.

http://ultradefrag.sourceforge.net/en/index.html

Seems it even offers a terminal interface for the real nostalgic kick.

[Vexs]

Hah, that's fun. Who doesn't like a terminal gui?