Skillshelv.es is a web application using Fluidinfo's (then very) novel globally writable database. The concept I designed combines a means of skills presentation with a book discovery and won me the second prize of the O'Reilly Fluidinfo API competition (an iPad!) If you look closely, you will notice that some of the concepts I introduced can now be found in very similar form on O'Reilly Media's website :)
Skillshelv.es was my first experience with Google App Engine, as well as my first confrontation with the challenges of managing a .es domain. Avoid both if you can. It was also the first time I used yellow as the base color for a website. You be the judge on how that went.
Unfortunately, I've never had the time and energy to realize the project's potential, and the site certainly hasn't exactly been a blockbuster success. If you feel that you can do better at running a book discovery website is your calling (tons of Amazon referral credits are just around the corner!), you should get in touch with me.