In the whole Godfather there were a few funny moments.
part 1
When clemenza is making pasta and he is trying to teach michael and then sonny is like cut the crap, but in the end he takes a piece of bread and dips it in the sause

When Don Vito slaps Johhny and says you can act like man then mocks him by saying what can i do thats a classic

when one of michaels bodygaurds in sicily said sicilian women are more dangerous than shotguns....something like that

Part 2

When frankie is sleeping during the partty

Part 3
Vincente whole meeting with joe zaza it was funny

and michael telling johnny he is gooing to in kitchen to listen to some tony bennet records

and when michael tells kay maybe they should fear you

thats some of them