Well, I finally got round to it. I started developing The Carbon Diet 2 years ago (had the idea 3 years ago!), and it's finally spread it's wings and joined the world of open source.
After I'd been developing it for a few months, it became obvious that it was never going to be a commercial proposition, so it's been my intention to open it up for a very long time now. However, I was putting it off until "after I get it finished", or "after I tidy up the code", or any number of other reasons. Having a small child puts paid to all those plans, so I've finally bitten the bullet and released my dodgy code to the world as it is, warts and all.
The site is built in Rails, but it's pretty creaky. It was originally written in version 1.2 as I was learning, and a lot of the old-style controller and route code is still hanging around, waiting to be improved. I've started, but there is a long way to go to bring it up to a decent standard.
Anyway, if you use the site (or not!) and fancy improving it, now you can. Head on over to github to grab the code and join in. I hope to see you there!