What is it?
A new feature of Windows Live Spaces that let's you set up events eg you can set up a social gathering of some kind and invite people to it, and organise it all via your Space.
Now you might say "but I've seen this before on xxx website" and I'm sure you have. However a really useful feature for me is that it allows other people to contribute content eg photos to the event, not just you as the event creator.
Of course, it also handles invites and acceptances etc, plus has some templates and other pieces you may expect to find (and does it all very well), but the ability for others to contribute content is key for me.
What's cool about it?
Where do I get it?
Visit http://spaces.live.com then use the "events" button at the top of your space.