It's a DVD and it's free. All together there are 9 awesome animations.
To download it (using bittorent) go to http://www.galaxydynamics.org/gravitas.html
But of course, if you don't feel like downloading it, you can pay them fifteen bucks and they will send you a DVD.
Example images: (http://www.galaxydynamics.org/gallery/images/FutureSky.jpg)
(http://www.galaxydynamics.org/gallery/images/cosmoslice_red_small.jpg)
(http://www.galaxydynamics.org/gallery/images/xy_02701.jpg)