If you're one of the people that didn't crash the server a few days ago to see "Dr. Horrible's Sing-Along-Blog", I highly recommend checking it out before it's gone. From the mind of Joss Whedon (Buffy the Vampire Slayer, Firefly), it's a 3-part musical comedy. Neil Patrick Harris is stellar as Dr Horrible, a villain trying to get his foot in the door at the Evil League of Evil. Felicia Day (of The Guild (among other things), which is a hilarious online sitcom that I also recommend, especially if you're a gamer) also turns out a great performance as Penny, the girl of Dr. Horrible's dreams.
It is definitely worth the watch!