All three Acts of
Doctor Horrible's Sing-Along Blog are up, but only for this week-end! They will all be taken down on Sunday night at midnight, although the iTunes download will be available through July 29th. The whole point is to make it a short lived event, the free part is really to thank Joss' fans for their support during the writers' strike. And of course the iTunes downloads, and later the DVDs, will help pay for the technical and other expenses on the project (if there is actual money to made then all the money will go to those who created this, not to the studios or networks, because they were NOT involved!).
Seriously, take the time to watch it now... it is really something special!