I never watched many episodes on Cartoon Network because I had them all downloaded and I was planning to get the DVDs. Now that I have them, I've been pleasantly surprised that like Simpsons, many episodes have alternate versions of the theme over the credits (which Fox of course never played). So far, I've ripped the medieval, rap, and another straight from the DVD to MP3. Not with hooking up a player to the computer, but by decoding the AC3 to a wave and encoding that into an MP3, so no static or anything...48khz/192kbps. But this stuff is copyrighted, so you risk being arrested if you download it and you don't own the DVD! But we're all honest boys and girls so we know that would never happen.
So remember, MP3s don't kill people. Dangerous minorities do.
Warning: MP3s are extremely dangerous. Do not purchase, own, clean, operate, or be near MP3s at any time.