YouTube - To celebrate 1 billion views, a tiny dancing Psy was added to the video page for Gangnam Style.
Makes sense to commemorate such a record being set.
iTunes - When adding a free item to a Wish List, an alert reminds you that you can download it right away.
I love the copy of this message, as well, subtly suggesting a reason you may want to download it immediately.
Flickr - The favicon turns into a live indicator showing the progress of the upload.
iOS - The feature Speak Selection (on Settings > General > Accessibility) shows the characters of the fable The Tortoise and the Hare for the voice speed settings.
/via Victor Boaretto
The original 1984 Mac used the same iconography in its control panel for keyboard repeat rate:
Mac image courtesy of Toasty Tech