So, I was watching the new Castle the other day and I picked up on a nice little easter egg from the previous Captain Reynolds (Richard Castle in Castle). The episode kicks off in a convention where there is a murder on a fan re-creation of some (assuming made up) space ship series called Nebula 9. Now when this ep started I immediately thought of Firefly, given the main cast in Castle AND that the fiction sci-fi was a spaceship one (With enemies named KREAVERS). Then I noticed the hint as Castle bashes Nebula 9 as a short lived series with only 12 episodes... And that he is fans of "good sch-fis" such as "Star Trek, Battlestar, and that Joss Whedon show."
Bwahaha.
Also note that he bashes on Nebula 9 for being canceled a "decade ago after only 12 episodes."