My brother and I just deployed a couple of web apps that we built together.
They all revolve around the same concept: random items are displayed and the user rates them from 1 to 5. We call it hugging or ditching. Once the users get bored, they can look at the top 10 or the other huga*.com sites.
Hugacity.com makes use of pictures licensed under the creative commons. The other apps pulled their initial data from Amazon.
All the sites share the same core of code and were built on top of Rails 2.