ColourLoversAPI is a project mainly written in C#, it's free.
A C# API for the RESTful interface of www.colourlovers.com to browse colour palettes.
This is a Monodevelop/VisualStudio solution with two projects. I've only used the code once to generate a cover for my thesis (unrelated subject). At the very least it may serve as a nice sample application, either for RESTful interfaces with .Net or for drawing with Cairo.
A simple API to the RESTful interface of COLOURLovers.
Only a few system libraries: System.Web, System.Xml and System.Drawing (for System.Drawing.Color, can be easily replaced)
A sample application to ColourLoversAPI. It uses Cairo and Pango to draw an image and uses the ColourLoversAPI to determine the colours.
This is a somewhat old project so any Gnome2 era (or later) release of the following libraries should work: GTK, Cairo, Pango