Our library is pretty advanced. Perhaps they are like this everywhere now, and I just noticed it since having kids and more frequent visits. Each book has a bar code taped to the front cover, and there are large kiosks outside the library where you can scan books as you return them. When we are about to visit the library again, Parker helps me sort through our books at home, setting the "bar code books" aside so they can be returned.
Today, he was playing with his baseball helmet, spinning it in his hands.
Parker: Mommy, does this have a buckle?
Me: A buckle? Yes, it's just that we took it off for now since you wanted it off.
Parker: No! A buh - code!
Me: (seeing a bar code stuck to the inside of the visor) Oh! A bar code! Yes, it does.
Parker: (sadly) Does that mean we have to return it to the library?
Me: No, you can keep it.
Parker: (hopefully) Forever and ever?!
Me: Yes, forever and ever.