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 Hot Day
It was a stifling hot day and a man fainted in the middle of a busy intersection.

Traffic quickly piled up in all directions, so a woman rushed to help him.

When she knelt down to loosen his collar, a man emerged from the crowd, pushed her aside, and said, "It's all right honey, I've had a course in first aid."

The woman stood up and watched as he took the ill man's pulse and prepared to administer artificial respiration.

At this point she tapped him on the shoulder and said, "When you get to the part about calling a doctor, I'm already here."