Here is something I've been working on for a little while, getting Mono to work properly. Properly = with dbus so you actually runs some apps with it. Banshee, F-Spot, Gnome-do and Monodevelop appear to be working with very few changes :)
Banshee
F-Spot
Gnome-Do
Monodevelop
Some people were also asking whether Java works, and I can confirm that IT DOES.

I'm going to try StromOS today and I'm really happy to see that a bunch of handy mono apps is supported.
I like .NET, so I really appreciate Mono.
But does the Java UI really works? I mean can you run Eclipse or Netbeans by just downloading them?
I only tested Frostwire (only Java app I could think of at the time) and it worked flawlessly. When I get some time I'll test those apps and post some screenshots. Assuming they work that is.