FORTUNE -- Jonathan Mann has been writing an original song and posting it on YouTube every day since Jan. 1, 2009. On Tuesday he sang his second duet with Siri, Apple's (aapl) artificially intelligent personal assistant. (His first was posted two weeks after the release of iOS 5). Siri will be one year old on Oct. 4, and she still has a lot to learn about humans.
Thanks for Daring Fireball's John Gruber for the tip.