NerdDinner.com is an excellent example application, and WAY better than the usual "Hello World" crap that's traditionally included in most books. And, it's an Open Source Project, so it'll grow way past the initial demo shown in the Pro ASP.NET MVC book.
I have heard some say that the book's not worth it since the NerdDinner Chapter (Ch 1); which is available as a free download; is 164 pages of the total 420 pages of the book (not including the index); however don't be put off by this. The book is an excellent reference!! If you're looking to demistify ASP.NET MVC and get using it; then I totally recommend this book.
Excellent Job on the Book!!!