If you share my earthquake paranoia fetish, you'll be fascinated by Berkeley's Memento Mori (requires Java). It's a realtime (actually, delayed by about 30 seconds) seismograph, displayed in morbid black and white. It's extremely sensitive. The 500 pixel height of the chart equates to 0.0005mm/s of actual accelleration, so there's always movement, even if it's just from waves hitting the coastline 5 miles away, or storm fronts passing through.

If you don't have java, there's also an animated gif of the last five seconds of activity.