Calendar and event tools - "I'll be there!" or RSVP and other thoughts...

I would like to see an RSVP tool for the event listing (in addition to iCal export) so that anyone wanting to attend the event can subscribe, download iCal file, see others that have subscribed (and want to share lifts option?), inform the organiser, etc...

Having a location that can be used by a GMap (with a draggable location marker to identify exact location... ) very cool!!  especially if it can show others attending as well (to assist car sharing)