Doloto
http://msdn.microsoft.com/en-us/devlabs/ee423534.aspx

Loads javascript in parts - gains up to 40% in page load speed (nice to have)

An AJAX application optimization tool from Microsoft.

Doloto is an AJAX application optimization tool, especially useful for large and complex Web 2.0 applications that contain a lot of code, such as Bing Maps, Hotmail, etc. Doloto analyzes AJAX application workloads and automatically performs code splitting of existing large Web 2.0 applications. After being processed by Doloto, an application will initially transfer only the portion of code necessary for application initialization.