Udacity

Udacity offers open online courses and massive open online courses, or "MOOCs," for free. Udacity courses are pretty focused on computer science and math, with such titles as Intro to Computer Science, Algorithms: Crunching Social Networks and Programming Languages: Building a Web Browser. The site offers a final exam for all courses every eight weeks, and after passing the final exam, Udacity will send you a certificate of completion for your course.