With 'Our Idiot Brother,' Paul Rudd joins a distinguished club: noted comedians who have played complete morons. The consummate straight man has always had a goofy streak, but in his new movie, which opens in theaters this week, Rudd gets to play Ned, a well-meaning idiot whose utter cluelessness makes life hell for his three sisters (Elizabeth Banks, Zooey Deschanel and Emily Mortimer). After a stint in jail for selling pot to a uniformed police officer, Ned gets shuttled from relative to relative, wearing out his welcome at every stop with his constant bumbling.

But Ned's no new phenomenon -- from Charlie Chaplin to Will Ferrell, moviegoers have long enjoyed watching actors play dumb. To celebrate Ned's stupidity, we've put together a list of the biggest movie idiots, characters who make us feel smarter by comparison and stupider for having watched them.

They say you have to be pretty smart to play dumb, and if that's the case, these 10 actors undoubtedly belong to Hollywood's Mensa chapter.

Lloyd Christmas (Jim Carrey) in 'Dumb and Dumber'
We're not entirely sure which is which, but Jim Carrey's Lloyd always seemed like the dumber of the two titular idiots in the Farrelly brothers' ode to stupidity. And whether he's traveling cross-country looking for a girl named Samsonite or simply annoying everyone within a 5-foot radius, the perpetually stupid Lloyd certainly lives up to his movie's title.

Smokey (Chris Tucker) in 'Friday'
Well before Rebecca Black's "hit" song, Chris Tucker's Smokey was by far the stupidest cultural icon associated with the end of the work week. In 'Friday,' the fast-talking Smokey endangers the lives of both himself and his best friend Craig (Ice Cube) by smoking away the product he's supposed to be selling, but even he's not dumb enough to sell it to a cop in uniform.

Alan Garner (Zach Galifianakis) in 'The Hangover'
According to Ed Helms' Stu, Alan is "literally too stupid to insult." And for our purposes, that's no small compliment. Zach Galifianakis is dangerously dumb as the childlike Alan in the bachelor-party-gone-wrong comedy, and almost loses his future brother-in-law as a result. But like all good movie idiots, Alan eventually redeems himself as a card-counting savant who would make Rain Man proud.

Stanley, Joan, Buster and Petunia Stupid in 'The Stupids'
Based on an equally dumb series of books, 'The Stupids' made idiocy a family affair. This nuclear family of happy dim-wits stumbles on an actual conspiracy while attempting to track down their "stolen" garbage, proving that, at least when it comes to movies, it really is better to be lucky than smart.

Bluto (John Belushi) in 'Animal House'
Fat, drunk and stupid may be no way to go through life (according to Dean Wormer), but it seems to work out pretty well for Bluto. Despite a sterling 0.0 GPA, the 'Animal House' alum apparently still managed to be elected to public office. We're guessing that's because he also gives one hell of a (historically inaccurate) pep talk.

Carl Spackler (Bill Murray) in 'Caddyshack'
Bill Murray's done stupid with the best of them throughout his distinguished comedy career, but Carl Spackler is undoubtedly a special case. After all, this is a guy who gets outwitted by a gopher (repeatedly). But the spacey assistant groundskeeper at the movie's snobby country club once caddied for the Dalai Lama, so at least he's got that going for him. Which is nice.

Haru (Chris Farley) in 'Beverly Hills Ninja'
Another actor who always had a knack for playing bumbling doofuses, Chris Farley may not have been a ninja master as Haru, but the role let the sensei of the pratfall show off his considerable physical-comedy skills. Whether he's wielding swords, fish or throwing stars, Haru is a constant danger to himself and his companions as much as the bad guys (and sometimes more so).

Derek Zoolander (Ben Stiller) in 'Zoolander'
As the airhead male model who makes Fabio look like Einstein and proves it's entirely possible to brainwash someone who only has half a brain, Ben Stiller struck idiot gold with Derek Zoolander. He can't turn left or grasp the concept of a scale model, but luckily for Derek, he's also really, really ridiculously good-looking.

Brennan and Dale (Will Ferrell and John C. Reilly) in 'Step Brothers'
From Ricky Bobby to Ron Burgundy, Will Ferrell's made a career out of playing dumb. But as Brennan and Dale, a pair of 40-year-olds who still act like they're 10, Ferrell and John C. Reilly make an even more formidable dim-witted duo. The two middle-aged man-children may not be related by blood, but when it comes to stupidity, it's like Brennan and Dale were separated at birth.

Ned (Paul Rudd) in 'Our Idiot Brother'
The others on our list may be more accomplished idiots, but it takes a special kind of stupid to sell drugs to a uniformed cop. And even though Ned always means well, the good-natured hippie's main failing is that he's too honest. Like an overgrown puppy, Ned wreaks havoc on his sisters' lives without necessarily meaning to, but he's probably the most endearing idiot of our feeble-minded bunch.

Think we're stupid for missing your favorite movie idiot? Let us know in the comments.