Actor Nathan Fillion (Castle, Firefly) is describing the spread at Joss Whedon's legendary "Shakespeare brunches," semi-regular LA affairs where Whedon convenes his friends—actors and non-actors, writers and directors—to eat and drink and read aloud their way through Shakespeare's plays.

"We would simply sip mimosas and have a lot of laughs," Fillion recounted in a phone interview. "And Joss kept saying, 'I'm going to film one of these,' and like an idiot I thought he meant film us reading it. But that is not what he meant."

What Whedon meant was the new movie Much Ado About Nothing, a black-and-white, self-produced affair filmed over 12 days in Whedon's own home. "This was Joss' two-week vacation," Fillion said of the tight filming schedule. "He was filming The Avengers and he had to go back in two weeks and edit The Avengers. This is Joss' idea of a vacation, shooting a Shakespeare film."

Much Ado is a snappy, clever play, and quipmaster Whedon is the perfect director to take on the courtship of sharp-tongued Beatrice and equally acerbic Benedick. Whedon's contemporized Much Ado is full of sexual tension, misunderstandings, and only-in-Shakespeare scheming—the verbal sparring that Shakespeare thought of as "foreplay" hasn't been this much fun since Julia Stiles and Heath Ledger (RIP) went at it in 10 Things I Hate About You. The whole thing is high spirited, silly, and supremely easy to watch.

I didn't love Alexis Denisof's cartoonish portrayal of Benedick, but Amy Acker is fiery and fierce as sharp-tongued Beatrice. And Firefly vet Sean Maher's performance is a highlight, as the nefarious, scheming Don John.

Fillion plays Dogberry, the bumbling, officious local police officer who's constantly tripping over his second in command, Verges (a very funny Tom Lenk). Dogberry and Verges get some of the film's best bits, mining ample comedy from the simple fact that Fillion is about twice Lenk's size. (There's even a "fat guy in a little coat" moment—if that reference is obsolete, god help us all.)

"Stupid people don't know that they are stupid," Fillion explains of his portrayal of Dogberry. "Stupid people think that they're the smartest guy in the room. So I learned that that's very important, to play smart. The smarter you can play it, the funnier and more stupid you can come off. So I just focused on trying to be smart, and letting vanity play a large role in how Dogberry behaves."

If Much Ado has a fault, it's that Whedon coaxes such natural performances out of his actors that Much Ado's weirdest plot elements seem, well, extra weird. Perhaps to help explain certain bizarre moments—the whole fake funeral thing, for one—the characters are rarely without a cocktail in hand. Beatrice in particular has a careening sort of recklessness, as though the decisions she's making might not make much sense in the morning. In the spirit of this booze-soaked adaptation, I asked Fillion to come up with a Much Ado drinking game.

"Drink every time someone gets slapped," he suggested. "Drink every time someone falls down, drink every time someone gets interrupted. Drink every time someone uses a word we don't use in common English."