I'm working on a project that has a website in Rails and a C# GUI that use the same database and data models. I'd like to share the (active)models between the two parts. Any ideas on how this is possible?
IronRuby is exactly for that.
You will need to run Ruby on Rails with IronRuby (you can do that via IIS too) and then you can call your C# assemblies like they were Ruby libraries.
Some resources to get you started: