Talent-wise, the Tenenbaums have nothing on the Whedons. Most folks know Joss as the creator of all things awesome on TV (like Buffy the Vampire Slayer and Firefly), but his younger brother Zack also got the wunderkind gene—and now the two have teamed up for Dr. Horrible's Sing-Along Blog, a comedic musical web series about a crummy supervillain (Neil Patrick Harris) and his arch-nemesis, Captain Hammer (Nathan Fillion). Co-writer Zack took a moment to talk about Dr. Horrible, which hits the web this week before its eventual DVD release.

MERCURY: Can you tell me more about Dr. Horrible?

ZACK WHEDON: It was a result of the writers' strike. It started out as an idea, and then kept getting bigger and bigger—it really snowballed. Pretty soon Neil Patrick Harris and Nathan Fillion were on board—otherwise, it would have been just us starring.

What will the DVD extras be like?

We want to give people a lot of extra features, so they don't pay for something they've already seen. There's a lot of behind-the-scenes footage. There's also a singing commentary, where we sing the commentary.

Will there be lyrics at the bottom of the screen for sing-along action?

No, but that's a good idea. Maybe we could do that for one of the extras.

The web comic you wrote to introduce Dr. Horrible was very funny (myspace.com/darkhorsepresents).

Thanks. We wanted to show what Captain Hammer was like outside of his relationship with Dr. Horrible. It was a great experience. I'm used to writing for TV, where you don't see the finished product 'til months down the road.

Are there plans to continue on with Dr. Horrible?

We hope that people will like it, so we can continue on with the story. We have so many ideas for it! It might be in the same format—web episodes—or something else. Maybe even Broadway, if people like it.

I'm willing to bet that people will like it.

I hope so.