Mike Nelson's been on The Sound of Young America a few times, mostly talking about his books. I've never had the personal attachment to Mystery Science Theater 3000 that some have (coughJordancough), but I will say that he's pretty much the nicest funniest guy ever. Or at least, in my experience on The Sound of Young America he's pretty much the nicest funniest guy ever. (Here's one of the interviews, by the way.)
In the years since MST3K, he's kept himself busy authoring three funny books and most recently recording a few commentaries for campy DVDs like the original Little Shop of Horrors. Now, he's taken the latter occupation one step further with something called RiffTrax.
Despite its awful name, it's a fun idea. Nelson records commentaries for movies, and sells them as MP3s. You download them, put them on your MP3 player, rent the movie, and watch it while listening to your MP3 player. Then Nelson makes some funny jokes.
The first film in their soft, beta launch is Nelson's all-time favorite, "Roadhouse." The Patrick Swayze vehicle is certainly ripe for mockery. Check out rifftrax.com and enjoy!