I have watched my fair share of television shows, and I have never seen one as incredible as Joss Whedon's Firefly. However, even for short-lived shows such as this, there are many interesting tidbits yet to be learned.
1. Summer Glau's epic line fail!
Whenever the cast would mess up their lines, they would yell "Summer!" This tradition started when Summer Glau, who played River Tam, messed up at the end of a particularly tricky scene, forcing them to start over.
2. Firefly is 6 Seasons too short
As most of you know, Firefly was canceled during before the first season even got to finish. Joss Whedon had initially intended for the show to run for seven seasons.
3. Little Zac Efron was in an episode!
Some of you may have realized that Zac Efron played the younger Simon Tam in the episode "Safe." This episode actually marks Efron's acting debut.
4. Neil Patrick Harris auditioned
Neil Patrick Harris auditioned to play Simon Tam.
5. Most of the Cast's voices feature in D.C. animated TV shows
Most of the main cast of Firefly have voiced D.C. Universe characters in the animated TV shows. Nathan Fillion (Mal) voiced Green Lantern, Gina Torres (Zoe) voiced Wonder Woman, Alan Tudyk (Wash) voiced The Flash, Adam Baldwin (Jayne) voiced Superman, Morena Baccarin (Inara) voiced Cheetah and Black Canary, Summer Glau (River) voiced Supergirl, and Ron Glass (Shepherd Book) voiced a newscaster. The only two that didn't voice characters were Sean Maher (Simon) and Jewel Staite (Kaylee).
6. Chinese Language was used to bypass censors!
Chinese words and phrases were inserted in to both show that society is comprised of a union between America and China, and to bypass censors. The phrases, when translated, read from, "this is pretty f*cking dangerous" to "the explosive diarrhea of an elephant."
7. The DVD's were flown to space
In 2007, the Firefly DVDs were flown into space with an astronaut named Steven Swanson in a shuttle called Atlantis.
8. We find out the Shepard's real name
Shepard Book's real name is Henry Evans. That, along with the Shepard's past, is revealed in "Serenity: A Shepherd's Tale."
9. Bounty Hunter is named after Nathon Fillion's ancestor
In the season finale "Objects in Space," the bounty hunter Jubal Early is named after Nathan Fillion's ancestor, who served as a general in the Civil War.
10. There are plenty of Star Wars easter eggs!
Joss Whedon was inspired by Star Wars when making Firefly. In the pilot episode when Inara docks her shuttle on Serenity, you can see an Imperial shuttle flying overhead. You can also see Han Solo frozen in carbonite among background props.