When I see an event, sometimes I don't want to commit to attend quite yet. But there are so many groups that it is easy to forget which events you found interesting.

The idea is to allow a 'shopping list' of events. You can add or remove them from the list anytime. You can also ask to receive an email if something changes: if the event is cancelled, if it fills up, if a spot opens, etc.

Uses:
1) Keeping track of events
2) Reducing the pressure to 'commit early, cancel later if needed' which results in events filling up with non-comitted people - I've seen that gold-rush destroy a few groups.
3) You can data mine that info to see what types of events people find interesting. Group leaders can also see the statistics to get a feel for who is considering attending, or how much demand exists.