File path as MVC route argument
A route like
"Files/{*path}"will get the path as a single string. The * designates it as a wildcard mapping and it will consume the whole URL after "Files/".
For more information on ASP.NET's Routing feature, please see MSDN:
http://msdn.microsoft.com/en-us/library/cc668201.aspx
And for the "catch-all" parameters you want to use, see the section under "Handling a Variable Number of Segments".