Q: What did the paper say to the pencil? A: You’ve got a good point!\nWhat do you think is the punchline of the above joke?
Explanation: Pencils are used for writing. When the lead (now it is made of graphite) is sharp it is pointy, it has a point.
When someone says, “You have a good point,” it means that you have a good idea; the thoughts that you added to the conversation gave it something new.
This joke is funny because it plays with “you have a good point.” The pencil has a literal point (it is sharp); perhaps it also has a figurative point (a good idea).