Help with .net mvc routing

Question

I haven't been able to find something somewhat similar to rails nested resources. I want to be able to define routes like

Contributors/3/Activities

which is just simply ActivitiesController, Index, with Contributor_Id = 3

I know I could manually define this specific route (I wouldnt know how) but what I'm looking for here is actually some recommendations on getting a flexible solution for these kind of scenarios.