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 recruit who wasn't really meant to be a soldier...
A recruit who wasn't really meant to be a soldier went out to the rifle range for the first time. He missed every target and most of the hills behind them. Despondent, he said to the sergeant, "I think I'll just go and shoot myself."The sergeant said, "Better take a couple of extra bullets!"