One of my favourite programs is SubEthaEdit.  SubEthaEdit allows multipe users to edit the same document simultaneously (each user with their own cursor).  This actually works suprisingly well and it only takes a moment to get used to multiple cursors on the screen.  (Screenshot from Malte).

SEE takes advantage of Apple Rendezvous technology and looks for potential victims on the local subnet. In the best cases, these prospects will be the other people in the room, some of whom you do not yet know. As an ad hoc networking and collaboration tool, SEE is one of the best.  It is spontaneous, easy to use, mobile and interactive.

The biggest shortcoming (for some) has been the fact that it excludes non Mac users. This may change in the near future with release of the Rendezvous Windows Technology Preview 2 .  The inclusion of Windows users in a Rendezvous list would really extend its capabilities.  While it seems that it may be a while before a SubEthaEdit-like program is really available for Windows users, perhaps all of our enthusiastic stories can help drive it along.