The Dirty Vicar sketch is my favorite - that whole show is good.
Another good one is Blackmail - where they show films and get people to pay to stop showing them.
Upper Class Twit is very good too.
There is a lot of great Fawlty Towers stuff too - my favorite episodes are the Germans or the Psychiatrist . If you haven’t seen Fawlty Towers they are great. (it stars Cleese)
The killer joke…
– Bob
From the movies: “…then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe who, being naughty in my sight, shall snuff it.”
“Amen.”
Scroll back, java. I put in 2 cents for both Mr. Neutron and the Pet Ant/Michael Ellis episode.
Nobody ever notices me.
Amazingly, no one has mentioned the classic restaurant sketch, featuring all hell breaking loose over a slightly dirty fork … “never kill a customer.”
Only one brief mention of the courtroom sketch featuring Mr. Larch, Inspector Dim of The Yard, professional Cardinal Richelieu impersonator Ron Higgins, and defense attorney Cleese questioning a dead witness (“are you considering the question or are you just dead?”)
Long live the Pythons!
AHEM
::points in the direction of my user name::
Aside from that, I also love the restaurant bit, mentioned above, the dead parrot, and argument sketch.
But one of the best laughs I got was the doctor making a house call and he robs his patient. I would rate the whole sketch as one of my favorites, but Terry Jones was the doctor, he floats into the sketch on wires. At the end he goes, “Now I’ll just test your reflexes” and flashes the ladies, who respond with “Whoo!” and a startled jump. I laughed my ass off at that.
Crunchy Frog - wondered if you’d answer this thread 
Oh another great one - the Agatha Christie sketch - “I must ask nobody to leave the room…I mean, I must ask that nobody…I must ask that everybody…”