I've noticed that a substantial percentage of questions fall in "What should I learn next to improve my programming?" and "Where can I find good material for study to improve my programming?" and it'd be nice to compile a list of easily accessible material for weekend learning. I'll start the list with a wonderful set of course notes that covers pretty much all aspects of functional programming and a portion of formal verification with the interactive Coq proof assistant: CIS 500: Software Foundations.
easily accessible material for weekend learning? Here is a A good compilation