C'mon, this whole website is called "EduGeek" and I'm the first one to mention this? Surely, as geeks, we can all automatically be assumed to be raving fans of Firefly, Serenity, Anything That Joss Whedon Does / Says / Is Mentioned In, right? I only came accross this by chance when idly reading through the XKCD comments board:
And you've only got a day left to watch it! Then it's gone!