The switch/rocker deals on pop cans.(Sorry, I don't know the correct name for them)
It may not be the most exciting invention in our life time, but remember those awful pull tabs they use to put on pop cans?
You would pull them off, and there was NEVER a trash can nearby to put it in. So, people would just throw them on the ground. Those little suckers were sharp too. I have no idea how many times I stepped on them barefoot as a kid. I saved a lot of mine and made chains with them. Sometimes I would just drop them down in my pop can. My mother hated that. She would say "Don't do that! You'll choke on it".
Now they have the little rocker thing on there and it stays on the can. It cuts down on sidewalk litter too!