Punny Puns

This is "punny." A pun is a play on words. It exploits possible meanings of a word or words and uses to its advantage. It makes a joke out of words that sound alike, but have completely different meanings. In this case "rhombus" is used in place of "wrong bus." We all know that a rhombus isn't really a wrong bus, but any parallelogram with equal sides, which includes the square. This is what makes the joke funny. What jokes can you come up with using puns?