gnome-mame
Wrote a GNOME based frontend for xmame today using C#/Gtk#. View image
It’s a pretty simple project. I need to re-write the handling of the loading of ROM information as the current code isn’t very good and it’s slow. I’ll probably release it on SourceForge.net at some point.
I enjoyed using MonoDevelop and I found programming in C# a pleasure. Mono is a good platform, I wouldn’t be surprised to see more and more applications developed using it.