Brain or muscles?
The strong young man at the construction site was bragging that he could outdo anyone in a feat of strength. He made a special case of making fun of one of the older workmen. After several minutes, the older worker had had enough."Why don't you put your money where your mouth is," he said. "I will bet a week's wages that I can haul something in a wheelbarrow over to that outbuilding that you won't be able to wheel back.""You're on, old man," the braggart replied. "Let's see what you got."The old man reached out and grabbed the wheelbarrow by the handles. Then, nodding to the young man, he said, "All right. Get in."

1stPerson: "Do you know anything about...
1st Person: "Do you know anything about this fax-machine?"
2nd Person:"A little. Whats wrong?"
1st Person: "Well, I sent a fax, and the recipient called back to say all she received was a cover-sheet and a blank page. I tried it again, and the same thing happened."
2nd Person: "How did you load the sheet?"
1st Person: "Its a pretty sensitive memo, and I didn't want anyone else to read it by accident, so I folded it so only the recipient could open it and read it."