This will be a short entry, but I think that it might save some people some time when building out ASP.NET MVC websites.
If you find that Cassini is crashing when you are testing out your ASP.NET MVC Application here is one more thing to check. Look at your master page file, it is generally a good idea not to touch any of the code that gets generated by the Visual Studio Designer, but from time to time you may find yourself playing around with the code in order to minimize the amount of content is being pushed out to the client.
The Masterpage file still requires a <head> with the runat="server" attribute. This is required to render the content in the Placeholders within it. With that said, if you are to remove the runat="server" you will experience an error, in my case, the cassini web server would crash when ever I tried requesting a page with the invalid masterpage.
With any luck, this will help you out!
Happy Coding!