If you haven't caught up with it yet, today's the day to catch all three parts of Joss Whedon's online musical Dr Horrible's Sing-Along Blog, with Neil Patrick Harris, Nathan Fillion, and Felicia Day.
It gets off to a slow start but it's witty, glorious, and sweet. After tomorrow it'll be taken down and you'll have to pay to see it in one form or another - iTunes or DVD. I've seen it online and the thought running through my mind was that I'll probably buy the disc and watch it again, 'properly'.
Maybe it's just me, but I find that watching online content is like eating a sandwich grabbed on the run. And with anything that runs more than a minute, I start to feel like I'm being held up from all my other stuff.