Freespace Open is an upgraded engine for the game Freespace 2 made by the source code project. You'll need a copy of Freespace 2 as game assets are not included.

Many topics already exist on how to get, install and configure it.
However not a single one yet linked this awesome video to show off what it can do:

http://www.youtube.com/watch?v=qTIBv1JQwAo&hd=1

At first i thought it's a remake of FS1 trailer...

... and then I was like like OMG cat.

It's a recently made trailer, right? Who created it?

new link for video - old one seems down:

http://www.youtube.com/watch?v=xhAR8rWPluQ