Gallery: TV’s 12 Best Halloween Costumes

You have to give Lily (Alyson Hannigan) props for the full-on feather get-up, but really the award for authenticity goes to Marshall (Jason Segel). Too bad people kept mistaking him for a gay pirate.

Props to the struggling sitcom for choosing a costume idea that many of us normal folk would want to try but ultimately ditch for the effort (and closeness) involved.

Despite all their Chrismukkah revelry, The OC never had an actual Halloween episode--mostly because each season seemed to start around November. But Summer's (Rachel Bilson) Wonder Woman costume will go down in history as every adolescent geek male's fantasy: A popular girl trying to understand the guy she likes by dressing up as an iconic superhero.

The closest thing GG had to a Halloween episode, "The Handmaiden's Tale" was full of season 1 intrigue, namely when Jenny (Taylor Momsen) disguised herself as Serena (Blake Lively) to get into a party. Her costume was so good that Nate (Chace Crawford) kissed her without taking off her mask. Too bad it was the wrong girl!

I don't know how the boys of The Big Bang Theory ended up representing Batgirl, Wonder Woman, Supergirl, and Halle Berry's Catwoman, but this made us laugh.

Nathan Fillion slipped a not-so-subtle Firefly reference into Castle's Halloween episode when he stepped out dressed in his old costume from the show. The best is when his daughter skeptically asks what he's supposed to be, and he says, "...Space pirate!"

Emily Deschanel may be five years older than Rachel Bilson--and play a socially-awkward scientist, to boot--but her Wonder Woman costume is pretty bangin'. Plus, it was for an actual Halloween episode.

Oh, and David Boreanaz's character Booth is playing a nerd.

Ugh, Glee. The way they treated the iconic musical was horrendous--especially with dropping "transsexual" and other irreverently sexual references from the lyrics--but at least the costume department did something right.

AnneLynne McCord is such a good sport for donning outrageous costumes on the teen drama. In this great outfit from last season, she channeled Avatar to try to win the love and respect of geek Max (Josh Zuckerman).

In Blair's (Leighton Meester) fantasies, it's always Halloween, and she's always decked out in some Audrey Hepburn costume. This was the first time we saw into the queen bee's crazed head, and it didn't disappoint: Her Breakfast at Tiffany's look is lovely.

In an effort to try multiple pick-up lines on women, Barney (Neil Patrick Harris) dons his best Top Gun outfit. He's just bummed that Ted (Josh Radnor) won't "flight-suit up" as Maverick.

Poor Pam (Jenna Fischer) ran into the most awkward of problems concerning her Halloween costume in season 5: At first glance, she was a very clever Charlie Chaplin. But she soon discovered that she could never take off her hat, or else she'd look like Hitler. (Womp womp.)