A stylish introduction to the novelties of HTML5.
General collection of programming related 'stuff' - docforge looks interesting.
The Django framework in Python is quite nice, but needs, like all dynamic languages, a good way to debug for typos. The scratch module looks to be the simplest possible way to write a non DB backed web service, albeit with absolutely no support for safe concurrent data access as designed.
The HIPR Image processing textbook online.