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."

An offense
Late one Friday night the policeman spotted a man driving very erratically through the streets of Dublin. They pulled the man over and asked him if he had been drinking that evening."Aye, so I have. 'Tis Friday, you know, so me and the lads stopped by the pub where I had six or seven pints. And then there was something called "Happy Hour" and they served these mar-gar-itos which are quite good. I had four or five o' those. Then I had to drive me friend Mike home and O' course I had to go in for a couple of Guiness - couldn't be rude, ye know. Then I stopped on the way home to get another bottle for later .." And the man fumbled around in his coat until he located his bottle of whiskey, which he held up for inspection.The officer sighed, and said, "Sir, I'm afraid I'll need you to step out of the car and take a breathalyzer test."Indignantly, the man said, "Why? Don't ye believe me?!?"