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."

Blonde State of Mind
A blonde was bragging about her knowledge of international capitals.

She proudly said, "Go ahead and quiz me. I know all of them!"

Her friend said, "O.K. then, what's the capital of France?"

The blonde replied, "Oh, that's so easy! F."