We recently finished our unit on triangle centers in geometry. Students were asked to do a lot of discovery / investigative learning with Geometer's Sketchpad (GSP).
One activity we had students do was get into groups of three and using Google Earth and GSP, find the location that is equidistant to all three of their houses.
For most, this was a great way to have students collaborate and have direct meaning to the geometry involved in the lessons. We saw some excellent sketches, such as the example below.
Google Earth is a very useful tool for this type of task. We found it more user friendly than Google maps since Earth allows the user to pin more than two locations at a time.