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 woman had some problems, so she went to her doctor...
A woman had some problems, so she went to her doctor of twenty years.They had the following conversation: Dr.: Take the red pill after breakfast with one glass of water.Woman: Ok. Dr: Take the blue pill after lunch with two glasses of water.Woman: Ok. Dr.: Take the yellow pill after dinner with three glasses of water.After giving these instructions to the woman, she asks, "Can you tell me what's wrong with me Dr.?Dr.: Yeah. You do not drink enough water.