I usually keep a small box of these packing things from packages I get to use when I have to mail things. Lex is always trying to pop them as soon as I open anything. Since I had a big bunch after all the mailing going on before Christmas (and don't plan to mail much soon) I let him have the big box full to destroy. He was pretty excited. And his older siblings convinced him to share. Who knew loud noises could be so exciting?