At the beginning of the current academic year, Stanford organized 3 free online courses (based on three stationary Stanford courses): Machine learning , Artificial intelligence and Introduction to Database . All courses come with video lectures and homework. There are also exams for Artificial intelligence and Introduction to Database courses. After successful completion of any course, a certificate (digital-signed pdf) from the teacher will be sent.
And so, several more online courses were announced, which will start in January / February 2012.
We have a great chance to listen to some of the famous Stanford courses, sign up!
Update Thanks to recky , who noticed that several more courses have been added. One of the CS sections is on cryptography, and two from the Entrepreneurship section: