Among the themes of this documentary about America's original counter-culture satirical magazine, one of the strongest that strikes you is how different the times of today are – of political, moral and social hysteria, political correctness gone mad, etc.

Sure, we have the American late night talk show hosts and the occasional breakout fictionalised film that questions the status quo, but they all seem pretty toothless next to National Lampoon's depiction of drugs, sex, children, animals and any number of other sacred cows or hot button topics to attack politics, big business, the church and any other deep pocketed institution.

Like a cross between Mad Magazine and John Stewart, a medium with Lampoon's lowbrow humour and bravado is sorely missing in today's media climate – stills of some of the covers and stories will have you just as amazed at their daring as you are spluttering with laughter.

Starting life as a Harvard University newsletter, Lampoon was formed by the coming together of an eclectic, fun loving and angry group of artists and writers in the 60s. Their primary motivations seemed to be getting stoned and laid, but they reserved some energy to write urgently funny polemics about the state of the world and rub each other wrong way.

In the end it wasn't the ego clashes that bought the whole thing tumbling down. By the time Lampoon finally closed up in the 1990s (having passed through the ownership of several companies) it was a shadow of its former self, all the original firebrands having long since moved on or died.

Ironically, the movie gives you the feeling that because post 9/11 right wing socio-political rhetoric crowds the airwaves today, there's more of a need for a loud voice prepared to take aim at any hypocrisy or corruption – and make us laugh while doing it – than ever.

The other fascinating aspect of the film is the case it makes for National Lampoon spawning almost the entire satire/comic industry we've had on screens ever since.

When the company grew big enough to expand into other media it created a regular radio show, several albums and a live revue that featured very early work by the likes of John Belushi, Chevy Chase, Harold Ramis, Gilda Radner and Bill Murray (all of whom show up in some amazing archive footage).

You might associate those names with another famous comedy name, and you'd be right – Lampoon had no sooner made them all stars when novice producer Lorne Michaels came along and offered them all truckloads of money to appear in his new show Saturday Night Live, which has been the breeding ground for Hollywood comedy for 40 years.

Their first cinema effort – Animal House – gave us John Landis as a director (American Werewolf in London, Trading Places – which introduced Eddie Murphy to the world) and Ivan Reitman as producer ( Ghostbusters , Meatballs, Stripes). Caddyshack (1980) was made by a clique of defecting Lampoon talent and resulted in the same comic flavour, and National Lampoon's Vacation (1983) followed.

But the influence spreads much farther and wider. Two of the writers who ended up on The Simpsons worked there. Judd Apatow and mockumentary godfather Christopher Guest were fans (both appear in the movie). Political commentator and writer P J O'Rourke was an early editor.

The film also doesn't shy away from the darker aspects of Lampoon's life. Co-creator Douglas Kenney disappeared abruptly one day to secret himself away and write a novel, resurfacing months later in a miserable, drug induced paranoia. When he came back to Lampoon to far less respect than he'd left, he ended up moving away from the magazine and into the other media the company was exploring (he played Stork in Animal House).

Kenney died under mysterious circumstances in Hawaii in 1980, and Chevy Chase, just one of the famous talking heads in the film, recollects about what a good friend he was.

It's a time capsule to another era that doesn't wear rose coloured glasses of nostalgia. Nor would those involved want it to.