Harold and Kumar get the Munchies is the latest in a long line of bongsploitation movies. Anna Carey pulls up a pouffe, lies back with some Monster Munch and a large orange Aero and mulls over the best and worst of the genre

THE history of good-humoured drug films is not a balanced one. For example, very few people make celebratory heroin movies. Films about smack are usually gritty, cautionary tales filled with dead babies and extremely unpleasant public toilets. There are what could be described as "coke movies", but they're really just drug movies by accident and are usually about horrible 1980s yuppies. The late 1960s saw the release of several acid-drenched films, from Head to Yellow Submarine, but that sub-genre was somewhat short-lived, perhaps because acid's effects are just that little bit too freaky on the big screen. But there's another drug with a strong influence on 1960s pop culture which has inspired a surprisingly successful cinematic genre all of its own. Nearly 30 years after Cheech and Chong first took off in their dope-powered van, the stoner movie is still going strong after several smoky decades.

From over the top condemnation (Reefer Madness, which sadly isn't quite as hilarious as you think it's going to be) to hazy celebration (the aforementioned Cheech and Chong's entire oeuvre), the history of cinema is filled with people skinning up, getting high, and giggling inanely while eating their own weight in junk food. Harold and Kumar Get the Munchies, which opens next week, is just the latest in a long, long line of films to depict dope smoking on screen.

So why are there so many films that celebrate smoking weed? Perhaps it's because cannabis is the most accessible illegal drug there is, meaning that more people will identify with a happy stoner than with a hopeless heroin addict. Or perhaps it's just because a few clever producers realised that stoned people are very easily entertained.

Stoner movies can basically be divided into three categories. There are the straightforward bongsploitation films. These are films about, aimed at and presumably made by people who are never far from their packet of Rizlas. They usually have "amusing" titles like Half Baked and The Stoned Age, and, with some exceptions, they are not very good unless you are incredibly stoned yourself. To the very stoned, however, the lack of quality is unimportant, as they will watch just about anything and laugh like a drain throughout. These films are usually based on the dubious premise that anything to do with dope is inherently hilarious, which it may well be after several enormous spliffs. However, the jokes are usually pretty witless ("He doesn't know there's hash in those brownies! Now he's stoned without realising it!"), meaning that few of these movies have anything to offer the non-drugged audience.

The second category of stoner classics includes the films which, despite having no obvious drug references, have been adopted by stoners world-wide. They include such innocent, if weird, childhood classics as Willy Wonka & the Chocolate Factory, Mary Poppins and The Wizard of Oz. The appeal of some of these movies is obvious. With its lollipop-licking Munchkins, flying monkeys and enormous field of poppies that make everyone very, very sleepy, The Wizard of Oz is a druggie delight. And as for Willy Wonka & the Chocolate Factory, well, its sinister undertones may induce paranoia in the more neurotic smoker, but its depiction of a world filled with sweets will appeal to anyone suffering from that junk-food craving known as the munchies. The stoner appeal of Mary Poppins is less obvious, but there's something about the scene where Dick Van Dyke dances with a bunch of cartoon penguins that has a strange effect on dope smokers. As soon as Van Dyke dons his stripey blazer, the average stoner is transfixed, mysteriously mesmerised by the nifty dance moves and gurning facial contortions of the loveable mockney chimney sweep and his avian chums.

Then there is the third category: good films that happen to be about people who smoke dope. These include the tragicomic cult classic Withnail and I, which introduced the world to the enormous joint known as the Camberwell Carrot, and The Big Lebowski, whose loveable hero, the Dude, is never far from his roach clip. Set on the last day of high school in a small 1970s Texan town, Richard Linklater's funny, nostalgic and dope-soaked Dazed and Confused is (loosely) centred on a school football star who has to decide whether to give up weed or stay on the team. Then there's John Hughes's The Breakfast Club. While some (not me) may debate its inclusion on a list of "good films", no one can deny that it offers a spectacularly unrealistic image of the effects of smoking a spliff. One toke of Judd Nelson's stash and Emilio Estevez is somersaulting around the library, performing impressive dance moves and, insanely, breaking a glass door panel simply by bellowing it at it.

The latest addition to this hazy genre is the immensely likeable Harold and Kumar Get the Munchies, the story of two weed-loving friends who, as the title suggests, get the munchies and realise that the only things that will satisfy their hunger are lots of burgers from their favourite fast food joint. So far, so stoner-flick-by-numbers - but Harold and Kumar is a stoner movie with a twist. Not only are its weed-loving heroes a banker and a medical student rather than the usual perpetually stoned layabouts, but banker Harold is Korean-American, his medical friend Kumar is of Indian origin, and the film's depiction of race in America is smarter, funnier and more complicated than the vast majority of Hollywood movies.

Although somewhat let down by some pointlessly unfunny gross-out gags and a few homophobic jokes, it's still a very funny film whose humour is based on more than the fact that these guys like to get really, really stoned - they also ride a cheetah through a forest, get arrested for jaywalking by a racist cop and encounter Neil Patrick Harris, former star of Doogie Howser MD, who plays himself in a truly hilarious cameo. Yes, it's a bongsploitation flick - just look at the title - but it's also funny and surprisingly charming, allowing it to fit into the last category too.

But while Harold and Kumar is highly entertaining, it's not the most accurate depiction of stoner life on screen. No, for a realistic look at the dazed and confused, one has to go to the small screen. A sharp contrast to The Breakfast Club in many ways, the wonderful 1999 TV series Freaks and Geeks showed high-school stoners as they really are. The show centred around two teenage siblings - Lindsay (Linda Cardellini, now starring in ER) and her geeky little brother Sam - in suburban Michigan in 1980. Straight-A student and "Mathlete" Lindsay starts hanging around with the school "burnouts" (the eponymous freaks), and while she's charmed by their Who-and-Zeppelin-loving cool, she realises that when they've been smoking pot constantly for several days in a row, they're really kind of annoying. But they're also rather appealing. The episode in which Lindsay finally smokes a joint herself ("What if all the world is a dream and it's not even our dream - it's that dog's dream?") is one of the most entertainingly accurate depictions of getting stupidly high ever captured on camera.

Freaks and Geeks shows the perpetually stoned as more than the usual "hilariously" blank-eyed burnouts who say dude a lot - the characters are always funny, real and sympathetic - but it also shows them as kids who play air drums to Rush, talk about drugs all the time, copy all their homework from their long-suffering friends, and try to woo potential girlfriends by singing along to Styx songs - with actions. In other words, Freaks and Geeks shows that when you're always stoned, you're kind of an annoying idiot with terrible taste in music and all your non-stoned friends will eventually get sick of you. And let's face it, that's something you'll never really get from a film with a title like How High.

Harold and Kumar Get the Munchies is released next Friday