University level C programming course for free online
The University of New South Wales in Australia is running their first year computer science course online for anyone. It's taught by the awesome Richard Buckland and covers C programming, problem solving, machine code and many other topics.
C assignments are submitted online and automatically marked. The next class starts on December 3rd and you can enrol here: https://www.openlearning.com/courses/unsw/computing1
You won't receive any university credit however Richard is a great lecturer and his courses are tons of fun!