While at my parents' house, we found the box from Noah's new car seat. Since kids always seem to love boxes, we pulled it out to see what Noah would do with it. At first, he didn't seem to have much interest in it. So I got in the box to show him how much fun it could be.
He still wasn't convinced of the fun that could be had inside the box. So we threw his ball into the box. That was the push he needed. He went right in after it.
If only children came in boxes like this with directions included.