Normally, an internet musical might sound like a terrible idea. However, since the one mentioned above - Doctor Horrible's Sing-Along Blog - has been written and directed by none other than Joss Whedon, I absolutely cannot wait!
We already know that Whedon has a knack for musicals (Buffy's Once More, With Feeling). Combine this with the fact the musical will be starring HIMYM's Neil Patrick Harris and Firefly/Serenity's Nathan Fillion and I can smell an instant internet classic.
Whedon says he wrote the musical during the strike and it will consist of three 10 minute episodes. Though he is vague on specific plot details, he revealed that it will focus on "the story of a low-rent super-villain, the hero who keeps beating him up, and the cute girl from the laundromat he's too shy to talk to."
It is still unknown when the first episode will be available for viewing.