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."

Buy machine factory
An American manufacturer is showing his machine factory to a potential customer from Albania. At noon, when the lunch whistle blows, two thousand men and women immediately stop work and leave the building.

"Your workers, they're escaping!" cries the visitor. "You've got to stop them."

"Don't worry, they'll be back," says the American. And indeed, at exactly one o'clock the whistle blows again, and all the workers return from their break.

When the tour is over, the manufacturer turns to his guest and says, "Well, now, which of these machines would you like to order?"

"Forget the machines," says the visitor. "How much do you want for that whistle?"