Here's a look at what they're doing now:

Whedon, who was already a cult hero before Firefly thanks to his series Buffy the Vampire Slayer, just became a household name thanks to his critically acclaimed writing-directing job on The Avengers. The Marvel super-hero mashup has been sweeping box office records; it set the all-time best opening weekend in the United States with $207.4 million, is hurtling past $800 million and could hit $1 billion by Sunday.

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Nathan Fillion, a frequent Whedon collaborator, played Captain Malcolm Reynolds, the brusque and charming lead space cowboy in the series. He is now the title character in ABC's crime comedy-drama Castle, employing his patented mix of heroism, sly sense of humor and touch of insecurity to great effect; the show was just renewed for a fifth season. He'll also star in the next Percy Jackson film, playing a Greek god.

Similarly, Alan Tudyk, who played the ship's ace pilot Wash, plays a strong supporting role on ABC's Suburgatory, which was also just renewed.

Tudyk's wife on Firefly, played by Gina Torres, has two series on her plate; she will return next month for another season of USA's law drama Suits, as well as voice Airachnid in the returning cartoon series, Transformers: Prime. Her co-star on that series? None other than Adam Baldwin, who played the tough lunkhead Jayne Cobb on Firefly -- and just did a guest spot on Castle. He also just finished five seasons on Chuck.

Morena Baccarin, who plays a Companion and potential a love interest for Captain Mal, is now one of the stars of Showtime's hit Homeland, playing wife to Damien Lewis's maybe-turned terrorist lead.

Jewel Staite, who played the tough girl with a soft heart Kaylee on the show, is now starring in the nighttime soap The LA Complex. Originally a show from Canada, it hasn't performed as expected on the CW in the United States, but has been given a second season up north.

Sean Maher, her love interest Simon Tam in Firefly, just starred with Fillion in Whedon's next film, the modern-day adaptation of Much Ado About Nothing, and has another film, Best Friends Forever (a drama, not to be mistaken with the NBC show) headed for theaters.

Summer Glau, Simon's damaged and mysterious sister, has guest starred in two episodes of Grey's Anatomy this season, and will star with Game of Thrones star Peter Dinklage in the film Knights of Badassdom.

Ron Glass, who played Shephard Book, has had a plethora of roles since Firefly ended, including arcs in All Grown Up and Dirty Sexy Money, and a guest spot in CSI: NY.

Email: Jordan.Zakarin@THR.com; Twitter: @JordanZakarin