I'm a decade or two younger then the rest of the crowd here, so for me its things like Jolt Cola, CB radios, and payphones.
I had to explain to some of the teens at work that a wise investment is to buy a cheap corded landline phone for when the power goes out just in case the cell phones die as well. They were wondering why until I told them that they're generally the last things to go out even in a power outage and could wind up saving their necks some day if they needed to communicate with the outside world and couldn't charge their cell phone.