Metal Gear Geo is a Geocache where the person who finds the "cache" must proceed through video clues followed by auto-loading map coordinates.
I started the game with the intent of making it cross-phone compatible. At the moment it is only iPhone 3G compatible, and there is only one location you can view it in too; in a wooded area somewhere in Raleigh North Carolina. I'm very close to figuring out how to best display coordinates on older phones; maybe I'll finish it over summer.
If you want to try it out while you're in the Raleigh area, type in www.rgbk.org/mg

The video above is a walkthrough. It contains spoilers. Also, I recorded it with my cellphone. The quality is low. Sorry.