Have you seen this 'nym words' page?
I stumbled on a website I thought you and your students might enjoy. It provides humorous examples of "heteronyms" ( I never kenw that word before!) - words that are pronounced differently according to their meaning, for example, close meaning "nearby" as in "close to you" or "shut"as in "close the door"; The "s" is pronounced like an /s/ or a /z/ depending on the meaning. The sentence from the website using both is: "They were too close to close the door."
Well, that is a garbled explanation, but check out the website http://avko.org/Info/fun_with_english_heteronyms.htm and you will find many more sentences for you and your students to practice.
No, thanks for the tips.