You could use a catchall route to capture everything that follows the wiki part of the url into the id token:
routes.MapRoute(
"Wiki",
"wiki/{*id}",
new { controller = "Wiki", action = "DbLookup", id = UrlParameter.Optional }
);
Now if you have the following request: /wiki/AS/400 it will map to the following action on the Wiki controller:
public ActionResult DbLookup(string id)
{
// id will equal AS/400 here
...
}
As far as /wiki// is concerned I believe you will get a 400 Bad Request error from the web server before this request ever reaches the ASP.NET pipeline. You may checkout the following blog post.