You Garmin fans will probably turn your noses up at this, but I love it anyway...
I discovered some GPS software for my phone (which obviously has a GPS receiver built in), and then further discovered I could load
any type of map I wanted, including aerial photos... so I did. Calibrating it was simple enough, so now I have an aerial photo of my neighbourhood calibrated to the GPS receiver, which is really neat because I can run around the streets and have the GPS trace marked out on the aerial photo as I go. And if I'm not too out of breathe, I can still make phone calls too
The screen shot is tad ordinary, but shows part of one of my run routes (walked, in this instance, in order to calibrate the beasty) with the GPS trace shown in red. It's kinda weird - almost like spying on yourself from on high.
Probably no real prizes for accuracy (seems to be +/- a "few" metres), but takes the blue ribbon for runners geekiness. I love it!