I know you guys are busy and everything, but here's something you could toss at some interns.
Simple (to start with) board games that could be purchased from the toy vendor and then carried. You could take them out and invite nearby users to sit down with you over the game. The game pops up as a flash dialog. Start with checkers! A scrabble-type game would be very popular I'll bet, especially if it could be played by up to 4 players. I even envision Game Night at Gregarious Grange where people mingle and play a variety of games with their Glitch friends.
(playing charades was fun. We need more of that sort of fun)