Ask HN: Best unintended use of your webservice?

I build a website called favstar.fm. Its purpose is to provide feedback on tweets - and easily show who is favoriting and retweeting your tweets.

This morning I woke up to discover a Japanese user has been using it as a canvas. Visit this tweet and click on the 'others' link next to retweets and you'll see a cool picture that they've put together by carefully setting up avatars for over 60 Twitter users, and then making them retweet a tweet in just the right order.

http://favstar.fm/t/30772880274886656

Has your webservice been used for something totally different than what you intended and produced a nice result?