In the unlikely event that there's someone in the world that hasn't seen this, I'd like to fix that. Watch it. NOW. For those who aren't familiar, this is a Joss Whedon brain child, so if you liked Firefly/Serenity, Buffy, or any of his other works, you will love this. Besides, that's Doogie Howser as Dr. Horrible! He has a Ph.D. in Horribleness, you know.
Dr. Horrible's Sing-Along Blog