Just a quick thing that I found for you today.
You can watch the complete catalog of South Park episodes. The only exception is some of the newest episodes will be posted in about a month or so after their original air date.
The website to check it out for your self is http://www.southparkstudios.com.
I watched a recent episode and scanned through another and the quality was pretty good. You couldn’t expand to complete full screen, but the image quality was good nonetheless.
If you are a fan of the series, this is worth checking out.