Support for social events

One of the things I most want to do with Social Networks is support events (camping, parties, trips, etc.) that a bunch of my friends will attend or have attended.

* Events should have their own social groups that are distinct from the invitees'/organizer's social groups.
* Events should have their own social group classes -- for instance new events of "Ski Trip" class might suggest that prior ski trip attendees get invited.
* Events should have their own "forums" or "discussion threads"
* Events should have their own media albums (photo/video/audio etc.)
* Events should not "fall out of view" after the event passes.
* Past events should be able to be added
* Event organizers should not have to have the invitee in their social groups, invitees should be able to receive an email with an "event key" that would allow them to "join" or attend the event. The "inviter" should not need to know the invitees social network user name to invite them, just have the system email them the "event key" in the invitation.

Perhaps I am not thinking big picture enough; perhaps there should be a method to extend similar functionality to "groups" (e.g. high school class, drag racing fans, etc.) The whole concept of not having to know a person's social network user name, just send them an email with an invitation "key" I think could be very worthwhile.