I still can't be sure what makes this film so endlessly watchable. It was another of the films I recorded by setting my portable stereo up in front of the TV while playing the VCR copy, replaying the recording so many times in my bedroom I could speak the whole thing including sound effects.

I was always a big Chevy Chase fan and am still disappointed that of all the actors of his class and era, he never performed with Bill Murray. He was never a great actor, playing variations on the same smarmy, not-terribly-smart theme he does here, but it was a shtick I never got tired of.

He plays Emmett Fitzhume, a low level diplomat in Regan's Washington who gets by with the seat of his pants – just watch him pretend the microphone's cutting out during a press briefing so he doesn't have to reveal he has no idea what he's talking about.

Aykroyd is Austin Milbarge, a civilian code-breaker working in the bowels of the pentagon itching to do something less boring for national security than working code breakers out of cereal boxes for his smarmy military employer.

When the pair unexpectedly team up during an exam to identify field agents, they catch the eye of Ruby (Davison) and Keyes, two recruiters looking for a pair of idiots to send into deepest darkest Russia. US intelligence has spotted a huge missile in the snowy forests and while they send real agents in to disable it, they need two disposable fools who think they're on a mission but who will attract so much attention with their ineptitude they'll provide cover for the real team.

After being rushed through training, the pair are unceremoniously dropped in the middle of Pakistan to make their own way north. Against all odds their wits and naiveté keep them safe until they connect with the real team, reduced to a single member, babe (and Aykroyd's wife) Boyer (Dixon). But back home, a slightly unhinged General (Forrest) has more sinister plans to guarantee the American way of life.

There are so many lines and gags it's hard to keep up, most of them straight players bouncing off Chase and Aykroyd's mugging and goofballing. None of it's particularly sophisticated but it's all very funny.

It was Bob Hope's final appearance on film, and it's definitely worth watching again – Sam Raimi, Terry Gilliam, the Coen brothers, Ray Harryhausen and Michael Apted are all in there somewhere too, following Landis' m.o. of casting fellow directors.