Following the tragic 2004 Indian Ocean tsunami, the world has focused on better ways to detect earthquake-generated tidal waves and warn people that might lie in their path. Cost has always been a major stumbling block, but now an Austrian named Michael Stadler may have come up with a way to detect a potential tsunami for virtually no cost. Almost all computer hard drives include sophisticated vibration sensors, and the data they provide allows the drive to maintain the required position for the read/write heads against the disks. Stadler has developed a program that can access and analyze this data, then share it with other computers connected via a peer-to-peer network. By comparing notes, the computers can ignore vibrations caused by something like your cat jumping onto the desk, and it can even differentiate between earth movements caused by a tsunami vs. normal seismic activity. If all of the correct factors fall into place, the system will sound the alarm, sending warnings to each of the connected computers.
Stadler's web site with the freeware download can normally be found here, but as of today it seems that interest in this story has caused his site to crash for now. Check back later if you're interested in grabbing a copy.