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."

Anniversary Flowers
A sad-faced Doug walked into a flower shop early one morning.

The clerk was ready to take his order for a funeral piece, based on the look on Doug's face, but soon realized his assumption was wrong as Doug asked for a basket of flowers sent to his wife for their anniversary.

"And what day will that be?" the clerk asked.

Glumly he replied, "Yesterday".