Here's a couple of different looks at the world of superheroes through different media!
First off, if you want to try some comic book theme rock 'n' roll, check out the Ray Wall Band's page here to hear some of their tunes, including their brand new song about Joker (their first DC song).
Meanwhile, if you enjoyed Dr. Horrible's Sing-a-Long Blog, Mercury Men Pictures is doing a fairly similar (in style and theme, not the same in plot or being a musical) video series called Captain Blasto, where a young man convinces a disparate group of fellows to dress up as costumed crooks and commit fake crimes so that he can stop them as...Captain Blasto. As you might imagine, complications arise!
You can watch the series here at CaptainBlasto.com.