Hahaha, these are the things that make having a kid so much fun.

When I was 4 or 5, my father showed me what he had gotten my mom for Christmas, an intricate looking diamond necklace. He told me to keep it a secret, and I planned to. On Christmas Eve, my mom jokingly asks me, "So what did your dad get me for Christmas?" to which I respond,
"I'm not going to tell you there's a diamond necklace in that box."
Oops.