Uh, oh!

Stupid old New England joke:

A man and his son are out in their New England pasture, picking up rocks and stacking them along the fenceline. “Daddy,” asks the son, “where did all these rocks come from?”

“From the glaciers, son,” Dad answers.

“So where did the glaciers go?” asks the son.

“Back for more rocks.”

Tip from the Instapundit.