[Dr. Boogie]

I got a few of the On Demand ones because I didn't already have any of the movies needed for the accompanying rifftrax. It's almost exactly like the show, apart from the lack of silhouettes and no character roles to stick to.

When I bought them (the On Demand ones that come already synced to a video file), they attach them to an account you make, and then you have a choice to download them in a few different formats (divx, mpg, mp4, and wmv) along with the option to download just an MP3 of the rifftrax. Once you have them, I don't think there's a limit to the number of times you can download each one.