Well, when in doubt, check out for yourself.
URL: http://gocosmos.org/ [1]
Released under BSD Open Source license
If you need to see in order to believe, check out the screenshots section:
http://gocosmos.org/Screenshots/index.aspx [2]
From the site:
"Why Cosmos?
Firstly because its fun! But there are many scenarios to use Cosmos in real world applications."
"Get source from CodePlex"
Links:
[1] http://gocosmos.org/
[2] http://gocosmos.org/Screenshots/index.aspx