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 woman entered the hospital to deliver her 15th child...
A woman entered the hospital to deliver her 15th child. "Congratulations," said the nurse, "but don't you think this is enough?" The woman replied, "Are you kidding? This is the only vacation I get each year."