This tribute gig is long. Really long. You just won’t believe how vastly, hugely, mindbogglingly long it is. I mean, you may think an episode of Midsomer Murders is long, but it’s just peanuts to this...

Yesterday, ape-descended life form Douglas Adams would have spent exactly 60 years on this utterly insignificant blue-green planet far out in the unchartered backwaters of the unfashionable Western Spiral arm of the galaxy. That is, had he not had the bad manners to depart it back in 2001.

It’s testament to his legacy, his passions and his gregarious nature that so many old friends wanted to honour the Hitchhikers’ Guide To The Galaxy author on this, the second most significant 60th jubilee of the year. That’s why this show had to start just after 5pm to fit them all in – and even then there were a couple of absentees, most notably Stephen Fry, who had to send greetings via video as he was away filming the Hobbit in New Zealand.

Equally packed as the bill was the Hammersmith Apollo auditorium. To this day, Adams has fan base as devoted as it is geeky, in all the best ways. There were plenty of towels on display, while at least a couple of men who should have known better had come in their dressing gowns, Arthur Dent-style.

The four-hour show, deftly hosted by Clive Anderson, was broadly divided up into segments to reflect Adams’s varied interests, starting with his conservationism. The night was raising money for Save The Rhino, a cause close to his heart, and the audience was shown video footage from Last Chance To See as a reminder of the fact.

For the science bit, Robin Ince introduced what was essentially a pocket version of his Infinite Monkey Cage tour. A Finite Monkey Cage, I guess. Ince has some cracking lines in his monologue about his own awe of science, which definitely flattered the intellect of this savvy crowd.

He introduced Jon Culshaw, first impersonating the absent Professor Brian Cox (who had been advertised but had to rush to Australia to ‘point at a volcano’ for his next BBC show) and then Patrick Moore speaking street patois, an easy gag but expertly done. That was followed by Simon Singh with a brief explanation of the expanding universe – and why modern cosmology proves Katie Melua wrong – and enthusiastic schoolma’amish comedian and space-themed-stamp-collector Helen Keen gushing away.

Adams’s comic work was discussed in a talk-show element with Anderson chatting to ex-Python Terry Jones and Kumars star Sanjeev Bhaskar, who was influenced by him, but never met him.

Among the tidbits we learned was that Adams once almost killed a couple of the Pythons after driving the wrong way down a motorway in a drink-drive incident; that the Kumars lived at No 42 in a nod to the most significant number in the Hitchhikers Guide saga; and that Bhaskar applied to be a non-speaking extra in the Hitchhikers movie – and got turned down flat. 

Interspersed through the night were various of Adams’ early sketches, performed from scripts – as if for a radio recording – by an an ensemble that included Rory McGrath, Angus Deayton, Michael Fenton Stevens and Philip Pope. Stephen Mangan, who plays Dirk Gently on BBC Four was due to have been among them, but illness forced him out, too.

There’s definitely a rarity value in seeing curios such as skits he wrote for the Seventies radio series The Burkiss Way or 1974 Cambridge Footlights show (in which Anderson and Griff Rhys Jones were performers) revived. The formats of these often haven’t weathered the passage of time particularly well – but despite their dated feel, the scripts still sparkled with an unmistakably inventive use of language, such as the railway worker demanding a ‘vocabulary rise’ so he could use more sophisticated words, or the way the Paranoid Society meeting conducted its business.

The comic highlight of the night, though, was John Lloyd – producer of QI and Blackadder, among many others – reading out extracts from The Meaning Of Liff, the book he wrote with Adams which found items, feelings and situations which need a word to describe them, but never – until their intervention – had one. Even better than the original suggestions were those submitted by the online community, proving genius breeds genius.

Another hit was, perhaps surprisingly for 2012, a spoof of the Bee Gees. The Hee Bee Gee Bees – comprising Deayton, Fenton Stevens and Pope, reprised their surprise 1980 Australian No 2 Meaningless Songs (In Very High Voices) – giving Anderson a flashback to his most infamous talk-show encounter.

Much less successful was Culshaw undoing the good he’d earlier done, thanks to a ploddingly written sketch in which Tom Baker’s Dr Who made dull observations on David Cameron and the like; a blatant plug for the forthcoming Hitchhikers’ tour that had one decent joke amid some garbled and over-long dialogue; and a rather awkward interview with Adams’s Cambridge-era writing partners Will Adams and Martin Smith in which producer Dirk Maggs proved he was no Clive Anderson when it came to questioning technique.

In his defence, this was an impromptu chat while the stage was set for the final musical section, based around the ad hoc band Adams used to assemble in his flat. This line-up included Procol Harum singer Gary Brooker – who still has an astonishing voice at 66 – Pink Floyd’s Dave Gilmour, blues guitarist Robbie McIntosh and singer-songwriter Margo Buchanan, one of whose tracks Adams once used for an advert he made for his beloved Apple Computers.

Some of their tracks were rather slow and contemplative, but Gilmour rocked it, a cover of Etta James’s I Just Wanna Make Love To You was wonderfully soulful and Whiter Shade Of Pale is still a skin-tingler after all these years.

All this and a troupe of eight tap-dancing rhinoceri, too. And somehow, when Douglas Adams is involved, that seemed in no way unusual.