I spent about 20 minutes writing a description of it but, hey, they've done a great job themselves.
http://universalis.actionroll.com
The regular discussion page for it is over at the Forge
www.indie-rpgs.com
I'm Stephen, a regular poster at the Universalis Wiki, follow the link from the main page. Say 'hi' sometime
Oh yeah, almost forgot to say, this is an amazing way to brainstorm adventures with your group. Or, if that's revealing too much plot for your tastes, Downtime