A man came walking up to the house when he noticed his grandfather
sitting on the porch, in the rocking chair, with nothing on from
the waist down.

“Grandpa, what are you doing?” he exclaimed. The old man looked
off in the distance without answering.

“Grandpa, what are you doing sitting out here with nothing on
below the waist?” he asked again.

The old man slowly looked at him and said, "Well, last week I sat
out here with no shirt on, and I got a stiff neck. This is your
grandma's idea.