elastic space has a list. A sampling:
Jabberwocky / Familiar Strangers: This research project explores our often ignored yet real relationships with Familiar Strangers. We describe several experiments and studies that lead to a design for a personal, body-worn, wireless device that extends the Familiar Stranger relationship while respecting the delicate, yet important, constraints of our feelings and relationships with strangers in pubic places.
Mamjam: One of the first location-based instant messaging platform for mobile phones. Asks the user to input location, and then creates links to others in the same space.
Dodgeball: Tell us where you are and well tell you who and what is around you. Well ping your friends with your whereabouts, let you know when friends-of-friends are within 10 blocks, allow you to broadcast content to anyone within 10 blocks of you or blast messages to your groups of friends.