Only just come across the [Glow Javascript library][glow] that the [BBC][bbc] released under the [Apache license][apache] a couple of months ago. It looks good, and has [excellent API documentation][glowdocs] as well as discussions of general usage for the majority of the tools.
In particular it has widgets for auto-complete text inputs, a simple class for validating form input and supports CSS-style selectors for referencing DOM objects.
Being that the BBC is mightily concerned with scheduled transmissions, Glow has an implementation of a timetable for displaying concurrent “tracks” of time data – I think this would complement the [Simile timeline library][simile] in various situations.
Seeing as I can’t do Javascript without [jQuery][jquery] or getting depressed, Glow is very interesting.
[apache]: http://www.apache.org/licenses/LICENSE-2.0.html
[glow]: http://www.bbc.co.uk/glow/
[bbc]: http://www.bbc.co.uk/
[glowdocs]: http://www.bbc.co.uk/glow/docs/
[simile]: http://www.simile-widgets.org/timeline/
[jquery]: http://jquery.com/