A lecture about English
A linguistics professor was lecturing to his English class one day. "In English," he said, "A double negative forms a positive. In some languages, though, such as Russian, a double negative is still a negative. However, there is no language wherein a double positive can form a negative."

A voice from the back of the room piped up, "Yeah, right."

Ashes to Ashes, Dust to Dust
After church, Johnny tells his parents he has to go and talk
to the minister right away. They agree and the pastor greets
the family.

"Pastor," Johnny says, "I heard you say today that our
bodies came from the dust."

"That's right, Johnny, I did."

"And I heard you say that when we die, our bodies go back to
dust."

"Yes, I'm glad you were listening. Why do you ask?"

"Well you better come over to our house right away and look
under my bed 'cause there's someone either comin' or goin'!"