I was two chapters into the "Agile Web Development with Rails" book and thought, "Why not create a web site?"
Hence the birth of www.CleanJokesForKids.com. It's not pretty and needs lots of stuff, but its there now. Kids can type in their favorite joke and rate other kids jokes. You can see the jokes filtered by the funniest, latest, or worst.
I've been very impressed with how Rails speeds development.