Earlier this year Stanford ran an experiment with some online courses - machine learning, artificial intelligence and databases. Instead of publishing classroom material on the web in a one way dump they tried offering a class experience with lectures, tests and graded projects.
I was intrigued and signed up - and so far I'm quite impressed. There are some teething problems and I don't always have the time to focus enough on my classwork but overall I'm quite happy - the courses are generally ipad friendly and I find it quite easy to plug in my headphones and find a quite spot for 30 or 60 minutes when I can. In fact I find it a great way to not watch TV :-)
Standford have since announced many more online courses and if they follow the same formula I expect to take a lot more over the next few months to refresh my memory and expand into some new areas.
If you're interested in data, machine learning, artificial intelligence or computer science in general I highly recommend you take a look at the following courses. If you're a startaholic (aka Entrepreneur, wannable entrpreneur or VC) then make sure you catch Steve Blanks Lean Launchpad course.
Computer Science
Entrepreneurship
Medicine
Civil Engineering
Electrical Engineering