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."

Aunt Dora went to her doctor to see what could be done...
Aunt Dora went to her doctor to see what could be done about her constipation. "It's terrible," she said, "I haven't moved my bowels in a week." "I see. Have you done anything about it?" asked the doctor. "Naturally," she replied, "I sit in the bathroom for a half-hour in the morning and again at night." "No," the doctor said, "I mean do you take anything?""Naturally," she answered, "I take a book."