This weekend I've mostly been reading Barry Cryer's reminiscences, listening to Round the Horne and I'm Sorry I'll Read That Again, and watching Morecambe and Wise, At Last The 1948 Show and Do Not Adjust Your Set, which has a) left me feeling a bit timelagged, b) given me the conviction that the reason Michael Palin and Tim Brooke-Taylor never did any TV together was not a happenstance of schedules but a deliberate move by David Frost to prevent the country being brought to a halt by sheer force of adorableness, and c) left me playing Six Degrees Of Barry Cryer. 
Also I realise I forgot to tell y'all about the rats; not long ago I was at the train station and a family of rats (at least 8 adults and 4 young) was frolicking around in a planted area; they were really playing quite charmingly and being generally sweet, if you could forget that they were, you know, RATS. (Look at him woffling his little nose! ... His RATTY nose.... And the adult giving the baby an apple core!... RATS EATING RUBBISH IN THE STATION OH GOD WHEN WILL MY TRAIN COME.)
The only people this is even slightly challenging for are stand-ups and sketch groups who've started up in the last five years and haven't done much collaboration, but even then I haven't been stumped so far- there are a couple of benefit gigs that connect most people to Phill Jupitus in less than 4, and from there it's mate in two: Phill's done Buzzcocks with Stephen Fry who's done ISIHAC with Baz. You might think it'd be less easy for theatre and film, but as Barry wrote for Morecambe and Wise, which gives him at most 2 to any Shakespearean actor you care to name, and used to write with John Junkin who was in A Hard Day's Night...
One could also do Six Degrees of David Frost, of course, but who'd want to?