There's no arguing that Monty Python is maybe the most iconic comedy group to ever grace the Earth, but there's often much debate around which sketch is their best.
"Twentieth Century Vole"
"Twentieth Century Vole" is not only hilarious, it's an insightful commentary into the pressures of being a screenplay (and sometimes novel!) writer. It reminds me not to take people's criticism too seriously, because they might be one step away from the looney bin.
"Parrot Sketch"
This sketch wouldn't be the same without John Cleese's outrageous declarations, facial expressions, and flamboyant personality. One of the classics that really shows off his talent as a writer, comedian, and actor.
"Argument Clinic"
Again, a clever sketch that breaks the 4th wall and becomes self-aware. My favorite part has to be Gregory Chapman's turn-on-a-dime attitude change. "Oh, sorry, this is abuse" gets me every time.
"Fish License"
Another nonsensical, yet side-splittingly funny sketch! There are some extremely subtle jokes and then there are bits that the whole family can laugh at, which is a common theme in a lot of Monty Python sketches. Needless to say, this one's a gem.