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."

12 Shots
A guy goes into a bar, orders twelve shots and starts drinking them as fast as he can.
The bartender says, "Dang, why are you drinking so fast?"

The guy says, "You would be drinking fast if you had what I had."

The bartender says, "What do you have?"

The guy says, "75 cents."