Observer readers' 50 funniest films: the top 20 (in reverse order)

20. Anchorman. Will Ferrell’s post-Saturday Night Live career was assured after the success of this first solo comic film. Although Elf’s appeal will probably endure, Ron Burgundy, a macho Seventies San Diego news anchor flustered by the arrival of a woman co-anchor (Christina Applegate), is likely to remain one of his most-loved, and quoted, creations. Photograph: Kobal

19. Dumb and Dumber. Jeff Daniels and Jim Carey in the title roles. You can hold it responsible for the glut of stupid humour that has cheapened American comedy since 1994, but the Farrelly brothers’ debut has gags to make even the loftiest humour purist splutter. I defy you to watch the bit about the dead bird, the Turbo Lax scene or the inspired coda with the tour bus while maintaining a straight face. Photograph: Kobal

18. Annie Hall. Diane Keaton and Woody Allen. Allen’s biggest critical and commercial success, this Oscar-winning semi-autobiographical comedy in which Allen, his ex-lover Diane Keaton and best friend Tony Roberts play versions of themselves. His first authentic hymn to his native New York, it created an influential new genre, ‘the relationship picture’, natural successor to the Thirties comedy of remarriage. Photograph: Kobal

17. There's Something About Mary. Cameron Diaz in the title role. Although notorious for its zipper and ‘hair-gel’ scenes, the Farrelly brothers’ smash-hit rises high above the gross-out standard thanks to a bounty of superb gags and a career-making performance from Ben Stiller. Cameron Diaz stars as Mary, the object of a high-school crush that grows into an obsession for Stiller’s hapless Ted. But he’s not the only one obsessed. Matt Dillon also stars. Photograph: PR

16. The Man With Two Brains. Kathleen Turner and Steve Martin. Famed doctor Michael Hfuhruhurr (Steve Martin), inventor of screw-top cranial surgery, falls in love with Anne Uumellmahaye’s disembodied brain (voiced by Sissy Spacek) after misguidedly marrying voluptuous ‘scum queen’ Dolores Benedict (Kathleen Turner) for lust. Martin gets to recite the worst poem in the English language: ‘The pointy birds are pointy pointy. Anoint my head, a-nointy, nointy.’ Photograph: Allstar

15. Planes, Trains and Automobiles. Steve Martin and John Candy. As the Eighties progressed and his stardom grew, Steve Martin toned down his manic comedy act. Here, he is the straight man to John Candy’s accident-prone shower-curtain-ring salesman. The highlight occurs when the odd couple share a motel bedroom and wake up together in a compromising position. Martin: ‘Where’s your other hand?’ Candy: ‘Between two pillows … ’ Martin: ‘Those aren’t pillows!’ Photograph: Ronald Grant Archive

14. Dr. Strangelove. Peter Sellers in the title role. In this devastating satire on the Cold War, the arms race and MAD (mutually assured destruction), insanity is in the air, on the ground and in Ken Adam’s subterranean War Room (which Reagan asked to see when he arrived at the White House). A stylistic triumph, occasionally over the top, but consistently and painfully hilarious. Photograph: PA

13. Groundhog Day. Bill Murray has a nasty moment in the shower. Bill Murray established himself as a genuinely skilled comic actor in this ingenious 1993 hit directed by his Ghostbusters partner, Harold Ramis. Murray plays morose weatherman Phil Connors, sent on another assignment to Gobbler’s Knob to interview a woodchuck. When Connors realises he’s living the same day over and over again, he first has gleefully malevolent fun and then learns how to love Andie MacDowell. Photograph: Kobal

12. Shaun of the Dead. Edgar Wright and Simon Pegg brought British comedy back to life with a jolt in this violently funny film, dubbed a ‘zom-rom-com’ by its makers. Shaun and his mates don’t realise at first that London’s denizens have been transformed into blank-eyed zombies; then all comic hell breaks loose. Sharp gags and erudite cinema references mix with gore to create one of the smartest black comedies of recent years. Photograph: PR

11. The Producers (original). Gene Wilder and Zero Mostel cower from Kenneth Mars. After sketch writing for Sid Caesar, Mel Brooks made a brilliant debut as a writer and director with this sparkling 1968 comedy about Max Bialystock, a scheming Broadway impresario (Zero Mostel) and a snivelling accountant Leo Bloom (Gene Wilder), who concoct a plan to get rich by producing a flop called Springtime for Hitler. The later Broadway musical won a record number of Tonys. Photograph: Kobal

10. Young Frankenstein. Peter Boyle, Gene Wilder and Teri Garr. Wilder and Mel Brooks were rightly Oscar-nominated for writing this wonderful homage to the black-and-white heyday of horror. Handsome cinematography and authentic production design lend a touch of class to the deliciously broad comedy, as Wilder’s latter-day Dr Frankenstein gets back to his Promethean roots. Photograph: Kobal

9. Duck Soup. Groucho Marx. In the Marx Brothers’ final Paramount comedy before Zeppo bowed out and the other three donned designer straitjackets at MGM, they run riot in Freedonia where the incomparable Margaret Dumont installs Groucho as anarchic president. Probably the peak of their career and the only occasion they worked with a great director. In Hannah and Her Sisters Woody Allen cites it as one of the things that make life worth living. Photograph: Kobal

8. Monty Python and the Holy Grail. Graham Chapman and John Cleese. Life of Brian may win more accolades, but Holy Grail is the true Python masterpiece. Co-directors Gilliam and Jones conjure a splendidly pestilential air as King Arthur (Graham Chapman) goes on his coconut-fuelled holy quest. Highlights include the limb-lopping battle with the Black Knight (‘What are you going to do, bleed on me?’) and the infamous French taunt; ‘I fart in your general direction.’ Photograph: Ronald Grant Archive

6. The Big Lebowski. Steve Buscemi, John Goodman and Jeff Bridges. The Dude abides in this wonderful pastiche of Californian noir, as Jeff Bridges gets drawn into a rug-related mystery with more tangled threads than anything Philip Marlowe ever had to contend with. Nihilists, weirdo artists and pederastic bowlers are just some of the oddities he meets along the way. The Coen Brothers have been justly lauded for this surreally stylish comedy. Photograph: Kobal

6. Blazing Saddles. Gene Wilder and Cleavon Little. Originally developed as a star vehicle for Richard Pryor (who gets a co-writer credit) Mel Brooks’s western pastiche proudly waves an anti-racist flag in the fart-filled air. Cleavon Little plays the sophisticated black sheriff saving a town of dumb white folk from evil railroaders with the aid of Gene Wilder’s ‘Waco Kid’. Photograph: Kobal

5. Withnail & I. Paul McGann and Richard E Grant demand cake from Llewellyn Rees. Bruce Robinson’s tale of two down-and-out actors who go on holiday ‘by mistake’ has inspired a true cult following – from the pilgrims who make misguided pilgrimages to Penrith, to the stoners who play the Withnail Drinking Game (match every drink taken on screen – including lighter fluid!) with hospitalising results. Photograph: Kobal

4. Some Like It Hot. Joe E Brown and Jack Lemmon - nobody's perfect. Billy Wilder had a bad time directing the wayward Marilyn Monroe; co-star Tony Curtis said love scenes with her were ‘like kissing Hitler’. But their experience perfectly reflected that of Curtis and Lemmon as the anxious musicians joining an all-girl band to escape lethal Prohibition-era mobsters – a fast-moving farce using the plot of a gangster thriller. Photograph: Kobal

3. This is Spinal Tap. Harry Shearer, Christopher Guest and Michael McKean. From guitar amps that go ‘up to 11’ to album covers that could be ‘none more black’, Rob Reiner’s genre-defining ‘rockumentary’ is an endlessly quotable gem. The lead characters are so convincing as gormless Brit rockers Spinal Tap that some American audiences didn’t even realise the film was a joke. Smell the glove! Photograph: Kobal

2. Airplane! Julie Hagerty and Robert Hays. Hollywood’s Seventies obsession with all-star disaster movies received a hubristic spoofing at the hands of the Zucker brothers and their Kentucky Fried partner Jim Abrahams. They struck comic gold chipping away at the Airport series of films, based on Arthur Hailey’s bestselling novels. Photograph: Kobal

1. Monty Python's Life of Brian. Are there any women here today? It’s nearly three decades old, but Life of Brian, which Observer readers have voted their number one comedy, still makes you feel as if someone upstairs is putting a big black X beside your name for laughing at it. The tale of Graham Chapman’s reluctant messiah, born a few stables down from the baby Jesus, has lost none of its impish comic power. Photograph: Allstar