If your interests are in TV shows or movies or something similar that one can collect on DVDs, building a simple CRUD web app to update a database should be a fairly simple application that will cover some basics like DB design and manipulation, AJAX if you want to send the requests without a full postback, and is something rather common in enterprise applications so it may be very useful.
The year the DVD came out, who wrote and directed what is on the discs, genre of the material, length, stars, extras on the DVD and many other things could go into the DB if one wanted to set up a library like system for an add-on that could be interesting in some ways.
