
Atmosphir is a free video game / creation tool for Mac & PC. Design mode lets you create enormous 3D platforming levels filled with fun gameplay elements like power-ups and fireballs, while Play mode lets you explore through the thousands of diverse user-created challenges being uploaded every day.
Atmosphir is currently in a private beta, with a worldwide release scheduled before the end of the year. So please sign up for the Beta (we are still sending out invitations every day on a rolling basis), and make sure to subscribe (via rss or iTunes) to our video feed for future updates.
http://minorstudios.com/journal/
http://www.techcrunch50.com/2008/conference/presenter.php?presenter=84