Gnome# is a .NET language binding for assorted GNOME libraries. It is free software, licensed under the GNU LGPL.
Building & Installing Gnome#:
The build is the traditional:
You may want to consider using configure's prefix option to install Gnome# using the same prefix as Mono. That way all of your .NET assemblies get placed in the same place, and you don't need to do any extra "configuring" o make it so mono can find your assemblies. In other words, doing something like:
./bootstrap-< version > --prefix=/the/path/that/was/used/for/mono
(Of course, replace "/the/path/that/was/used/for/mono" with whatever path which was used for Mono. This might have been "/usr", "/usr/local", or something similar.)