1. A linguistics professor was lecturing to her class one day. "In English," she 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."
(The joke is fairly well known but this version I found
here.)
2. Just a conversation from a friend's Facebook page:
A: I will go insane if I keep reading works of I. Kant!
B: Try reading something written by I. Can .
A: Should I read Obama's inauguration?
B: if you want to you can :)
Reminded me of some teacher's statement: "Can't is a Four-Letter Word not allowed in my classroom."
(Just in case: Four-Letter Word usually refers to a "bad", curse word.)