jQuery UI 1.9.0 is out, which adds new widgets, API refinements, improved accessibility, and hundreds of bug fixes. The new widgets are as follows:
There's a detailed jQuery UI 1.9 Upgrade Guide which lists deprecations. Oh, and the jQuery UI site has been refreshed as well!
This theme has a metallic finish that reminds me if iOS 6, and includes light and dark variations. It's also dubbed as Retina ready -- CSS3 gradients and high-resolution images have been used.
To find the best font size, a binary search is performed. The demo on jQuery.textFit's site is slowed down so you can actually see how the algorithm works, in reality it seems to run very quickly.
Vertical alignment and centred text are both supported, as are custom fonts.