I'm sure everyone's heard of this, but like me, never actually got around to trying it... so here's a link to a vid where it's been done for you :)
http://video.google.com/videoplay?docid=-4935715412555856092&q=pink+floyd
Some things to look out for are listed here.
Myself, I'm a sceptic in general and I've always been sceptical of this, but having watched it I'm now a little more undecided. There's a huge amount of links (and they come thick and fast in some places) - but on the other hand there are quite a few places where nothing happens, and few tricks 'missed', and quite a few facts about the recording that would make it a lot harder to accomplish than it would at first seem. I wouldn't put it past them anyway, what with all the Publius stuff :)
What does eveyone else reckon?