A few weeks ago, I had an "out-there" idea to try creating and selling a site at the same time. So far, it's not exactly raking in a major amount of cash:
At $100 with a couple of bids, it doesn't look like I'll be able to retire on it! That said, I haven't spent a great deal of time on it, and part of the idea of the experiment was to limit the amount of time the 'new idea' would distract me from other things. I did hope to receive a few more "audience requests" in terms of what to build on Flippa.com, though. Hopefully, things will heat up a bit during the final two weeks of the auction, but I don't think "flipping" web sites is really a business I want to be in. It's been fun to see how much you can build with how little, though, what with all the widgets and API's out there these days.
Since I'm a coder at heart, I also released some Ruby code that utlizes Google's stock screener API: https://github.com/davidw/google-screener - it's under the Apache license, and is kind of neat to play around with, I think, and is what I use to fetch information for the site.