Is there a .NET framework similar to Ruby's Sinatra?

There is a new framework called Nancy for .NET which is inspired by Sinatra and looks promising. But it is still in a very early state.

You can read more about it here: http://elegantcode.com/2010/11/28/introducing-nancy-a-lightweight-web-framework-inspired-by-sinatra/ and

There seems to be a host of these micro web frameworks on .NET now:

Nancy: Here is a HanselMinutes podcast with the creator Andreas Håkansson
Nina: "Nina is a web microframework for the .Net platform, inspired by Sinatra"
Kayak: "Kayak is an asynchronous HTTP server written in C#"
Manos: Interview with the creator Jackson Harper on Hearding Code
Jessica is "a micro web framework written out of curiosity in .NET, inspired by Ruby's Sinatra."

There is good blog article by Mike Hadlow where I picked up the above links and he goes into good detail on each. Just thought I'd shoutout these projects, it's exciting to see such development in the .NET world.

You may also want to check out OpenRasta. It is a nice, clean REST framework. I don't know if it uses the MS routing libraries or not, but from what I can tell it's routing syntax is very similar, if not identical. Also, it looks like IronRuby is capable of running Sinatra and Rack now, and the IronRuby website has instructions for getting it up and running, so an alternative may not be required if you want to run Sinatra in a .NET environment.