I just completed a fun project hooking up a dedicated low power, shoebox sized Windows Home Server to a University of California, Riverside project called QCN, or Quake Catcher Network. My home server now measures vibrations and sends the results to a central network. Very cool.
If you have a home server (or any recommended PC/laptop) and live in an area where the ground shakes a lot, you may want to take a look at using some of those cycles when your server is idle. More details on my setup and project at http://tekinerd.com/?page_id=123.