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."

A Dead Lawyer
A woman and her little girl were visiting the grave of the little girl's grandmother. On their way through the cemetery back to the car, the little girl asked, "Mommy, do they ever bury two people in the same grave?"
"Of course not, dear." replied the mother, "Why would you think that?"
"The tombstone back there said 'Here lies a lawyer and an honest man.'"