Firefly - the amazing "space western" series created by Joss Whedon - first aired on September 20, 2002.
Whichever idiot in charge of the Fox Network at that time axed the series after airing just 11 episodes. They even ran the episodes out of order (plus, they didn't bother to air the pilot until just as the show was canceled).
I grew up on re-runs of Star Trek: TOS, so that is my favorite tv show. Firefly is a close second.
Series executive producer Tim Minear shares some memories of the final moments of production in this piece from MTV's Splashpage.