Michael Arrington's got the leak with lots of screenshots and feature info. They are entering the social calendar space:

Whenever you create an event, we create a web page which you'll see when you click on the "more details" link on any event. This web page is only visible to you, unless you've invited other people to your event or made the event public, in which case you can use the page to share information about the event with people who are attending or the public at large. Note: you don't have to be a CL2 user to be able to see event pages, so you can use these pages to share information with anyone involved with the event, regardless of what online tools (if any) they use. (Ever wish your favorite local band would learn how to use HTML and publish their calendar? Once we get your feedback and open CL2 to the world you can help them do just that.)

Watch out eventful, zvents, fullcalendar, 30boxes, etc, etc.