About 2 years ago R. Tyler Ballance went to BarCampTexas and, finding himself with no place to stay, holed himself up in a coffee shop for the night and knocked up a demo application Bonsoir in about six hours.
When this app is running, it uses Apple’s Bonjour service to find other running Bonsoir apps on the network and allows swapping of AddressBook cards. The idea is that it would be useful at get togethers such as BarCamp for people to swap contact details.
Actually, this is prompted a little by guilt. I was looking through my iChat transcripts the other day and I said I’d do some work on it – and that was back in 2006.