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 man in the army asks for a pass
An Israeli soldier who just enlisted asked the
Commanding Officer for a 3-day pass.

The CO says "Are you crazy? You just joined the
Israeli army, and you already want a 3-day pass?
You must do something spectacular for that
recognition!"

So the soldier comes back a day later in an
Arab tank!

The CO was so impressed, he asked, "How
did you do it?"

"Well, I jumped in a tank, and went toward the
border with the Arabs. I approached the border,
and saw an Arab tank. I put my white flag up,
the Arab tank put his white flag up. I said to the
Arab soldier, "Do you want to get a 3-day pass?
So we exchanged tanks!"