Variation on a theme:

Some time back, we were in the kitchen talking about Corel dishware and how it was unbreakable. I was handling some, and I blithely tossed a plate onto the floor. It bounced, and remained intact. Everyone laughed. Some time later, several of us were in the kitchen discussing Corel, and my brother said, "Lemme show you what my crazy brother did." He threw down a Corel plate which, in fact, shattered worser'n glass. Everyone laughed.