Here is a logic puzzle I made up for my Math 173 students to practice with negation and the other logical connectives.
Tommy Flanagan was telling you what he ate yesterday afternoon. He tells you, "I had either popcorn or raisins. Also, if I had cucumber sandwiches, then I had soda. But I didn't drink soda or tea. Yeah, that's the ticket." Of course you know that Tommy is the worlds worst liar, and everything he says is false. What did Tommy eat?