I'm slightly addicted to jokes that have to do with the oddness of the English language. Therefore, I chose two sets of words that sound the same, or nearly so, but have entirely different meanings. One of my favorite words is "bow/bough." I can't think of a joke right now, but here's an example: "Jack, who was sitting on a large bough and holding his bow, bowed to the captain standing on the bow as the boat passed beneath him."
Sometimes I'm amazed at the number of people who learn English as a second language when they have to deal with things like the example above. I read an anecdote in Reader's Digest about a foreign student who gave up on English when he saw the following newspaper headline: "Bazaar Pronounced Success."