I have used this site as a class project in the past but lost the link. I was very happy to see that it has been put back on the web. It is a very excellent demonstration of seismology. Students calculate the distance to the epicenter of an earthquake plus estimate the magnitude by measuring information from simplified seismograms of actual earthquakes. This exercise gives the student a much better grasp of seismic data and how it relates to earthquakes. The site can easily be finshed in an hour and it is very easy to use. Grading is simplified as the student can print a "Virtual Seismologist" certificate which includes all of the data they measured along with their success rate.
The site is cleaner and seems to work more smoothly than when I first used it several years ago.