IMO, silly job interview and olympic hide and seek, or one in travel agency with Eric Idle and Michael Palin, forgotten the name but Eric Idle's character goes on for about two minutes
Most underrated Python sketches
I like the one where the gangster type people are planning a robbery where no crime is committed. Or something like that.
The silly job interview definitely: one of my all time favourite sketches. Well written, very silly and it even had a punchline, which is rare for them.
Off the top of my head, a few other vastly underrated sketches from the show would be Upperclass Twit Of The Year, The Argument Clinic, Self Defence Against Fresh Fruit, Mr Hilter and the Burglary Reporting sketch.
The thing is, I could list a load more that are just as good that rarely get talked about, because the show had so many quality sketches.
RAF Banter was one of my faves, and Tinny Words - Chapman just cracked me up 'gooorne, goooorne. Nice and woody!'
Lucky I didn't tell them about the dirty knife!
That one.
The Timmy Williams interview where Terry Jones is trying to pour his heart out to Eric Idle but keeps being interrupted. The piranha brothers, the joke that kills people, and the mountaineering sketch where John Cleese has double vision.
I'm surprised no-one has mentioned the Dead Parrot sketch - you rarely hear about that one. 
Funnily enough, with the exception of Nudge Nudge, I don't find the sketches that are supposed to be the 'classic' sketches particularly funny, Ministry Of Silly Walks doesn't do anything for me nor Dead Parrot
Kilimanjaro Expedition.
Quote: Jackson Neil @ May 26 2009, 8:54 AM BSTKilimanjaro Expedition.
"...both peaks of Mount Kilamanjaro"
"There is only one peak sir"
"Oh. Well, that'll save a bit of time"
The Pirana Brothers
The Special Olympics (ie the race for those with a weak bladder and the Deaf)
Cheese Shop
You sure you're not thinking of Upper Class Twit of the Year?
It's just that the Special Olympics is a real event for people with disabilities. You haven't been guffawing at blind hurdlers and learning disabled marksmen have you?
My favourite underrated sketches include The Mouse Problem, Ethel the Frog (The Pirana Brothers), The Upper Class Twit of the Year, Mrs. Nigger-Baiter Exploding and The Funniest Joke in the World.
I've just got the box set and am working my way through the episodes. I think most of their sketches are over-rated, and I can't ever remember actually laughing at any of them. Some of the episodes just drag on terribly. I'd up the pace by cutting the animation out, for a start.
Quote: sootyj @ May 28 2009, 10:08 AM BSTYou sure you're not thinking of Upper Class Twit of the Year?
It's just that the Special Olympics is a real event for people with disabilities. You haven't been guffawing at blind hurdlers and learning disabled marksmen have you?
God! No of course not but The Python sketch is funny isn't it, particularly the weak bladder one where they keep haviong to run into the bushes for a piss 
very un PC nowadays of course?