Amazon Light is an interface to Amazon.com’s search engine with a Googlish-UI (in fact, the original UI was so Google-like, the designer got a letter from Google’s lawyers…)
It’s all done with Amazon’s web services API, and shows why that’s a cool thing – in fact, I guess it’s a better demonstration than the Google API of why web service APIs are useful – Google was so spartan that people argued you could just as well use CGI and screen-scraping (parsing what you want out of the HTML Google returned).