Yet another brilliant site by Simon Willison. This time its a mashup of geodata and Wikipedia: wikinear.com shows you a list of the five Wikipedia pages that are geographically closest to your current location. It’s designed to be used mainly from mobile phones.
Built with OAuth, Fire Eagle and Django. You'll need a Fire Eagle invitation to use wikinear.com. (I have an account already but apparently no invitations to share -- or at least I didn't find any.)