Read the jQuery source like a book like a boss.
Make it better by contributing on GitHub.
Although this link has recently been circulated on twitter, please note that the project has not been worked on since August of 2011, when jQuery 1.6.2 was the latest version.
The idea for the project was to replace/enhance the jQuery source comments with more readable, descriptive, and educational comments. Tracking with jQuery version updates is a challenge since it's not just a matter of running the latest jQuery source through Docco.
But given the current interest I'll work on updating for 2.x!