I have an MComp in Computer Science. I would like to specialize in game programming. What online free video game design courses are there? I as thinking something similar to coursera.org
If you meant "design code for games" it's time to leave the classroom behind and just start writing; while there are broad guidelines on "how things are done" each game is basically a little R&D project of "how things are done for this game here." All a game programming course would teach you is how to program and you already know that.
There's also plenty of open sourced games out there to examine.
If you're talking about designing gameplay, systems or building levels the same advice applies, just start designing, with the exception that your R&D consists of playing other games critically and tearing their guts open to see how their systems work.
The answer here is that since you have a background already you are your own best teacher on how to apply what you know to the problem at hand.