The new R-rated comedy "The Watch" features a star-studded cast both on screen (Ben Stiller, Vince Vaughn, Jonah Hill and Will Forte) and off (co-written by Seth Rogen). It seems ironic then that the film's saving grace is a relatively no-name British comedian who gets fourth billing and has been tucked to the side in most of the movie's publicity.

The man's name is Richard Ayoade. He's mainly only starred in British television comedies, including the hilarious "The IT Crowd" and the cult-smash "The Mighty Boosh." However, he's due for more attention after his scene-stealing performance in "The Watch" that helps keep the film matinee-worthy despite itself.

Instead of Ayoade, the film follows Ben Stiller as Evan, a small-town do-gooder who minds his time creating and leading various neighborhood clubs and managing the local Costco. His picture-perfect suburban life gets turned upside down, though, when a guard at his store gets murdered. Distraught by the criminal act, Evan creates a neighborhood watch (the original title of the film, but it was changed after the shooting of Trayvon Martin) with the help of Vince Vaughn, Jonah Hill and Ayoade.

In between cans of beer and bonding chats, the quartet discovers the murder might be the result of a devious alien plot involving UFOs in disguise as average citizens.

The plot sounds like it could have some entertaining suburban satire along the lines of "Hot Fuzz" or "Edward Scissorhands," but the screenplay by Rogen, Evan Goldberg and Jared Stern barely touches on depth. Early in the film, for instance, Stiller notes in voiceover that he has several minority friends and is searching for an African-American to call his pal. There's a witty satirical idea in there about white America's dependency on minority relationships to prove their worldliness and goodness, but it's abandoned almost immediately after the first 10 minutes.

"The Watch" is far more interested in watching the four man-children run around Suburbia causing havoc, yelling and partaking in extended sequences of profane, probably improvised banter. Director Akiva Schaffer (most well-known as a writer/director for The Lonely Island, who make a cameo appearance) goes after those goals with an admirably goofy, and eventually contagious, spirit that helps some of the film's jokes hit their mark.

Stiller, Vaughn and Hill are all funny enough as well, but their on-screen comedic personas are becoming tired. Stiller is another stiff, easily flustered everyday man, and Vaughn is his usual fast-talking, wisecracking man's man.

Hill, despite being a comparatively new comedy star (his breakthrough roles in "Knocked Up" and "Superbad" came only five years ago), has his predictable jokes and quirks as well. It seems like a contractual obligation for Hill to yell at his on-screen mother at least once per movie (if this, "The Sitter" and the far superior "21 Jump Street" are to be believed).

They still manage to score some laughs, but their routines feel like exactly that: routine. The script doesn't help in some scenes, providing overlong conversation scenes and predictable set-ups, most notably an extended appearance by Evan's uncomfortably complementary neighbor (Billy Crudup) that results in an underwhelming punch line. Rogen and company also have a habit of finding extreme violence a lot funnier than I do (see the last half of "Pineapple Express").

Perhaps that is why Ayoade's performance feels so enjoyably fresh and lively. He's a new face with a new comedic sense. His dweeby presentation and dryly articulate timing and delivery easily results in "The Watch's" funniest moments. He's unfortunately the main character in a clunky mid-film plot revelation, but that's more the script's problem than Ayoade. For the most part, he is the film's saving grace.

And speaking of savings, "The Watch" would like you to know how great Costco is. The product placement in the film is rampant (Michael Bay would be proud). The main characters tout the undying virtues of Costco, as well as its immense selection, on several occasions.

It's not enough to ruin one's enjoyment of "The Watch," but it was certainly distracting as I attempted to enjoy the film with my delicious box of Junior Mints and a refreshing Sierra Mist.