Stupid phone tricks in the old days
One time in school, I was doing some work on the computers in an engineering lab and overheard some guys having a problem. They were working on some kind of fairing for a recumbent bicycle, and needed to get in touch with Boeing. Only trouble is, they had no idea how.
This was before the days of "just go to their web site" or "dig around in Webcrawler" or even "try using whois". None of those were options. I happened to know a few things about how to get things done with a telephone and decided to poke my nose into the situation.
First, I established that they wanted Boeing in Seattle, WA. They said yes, and I walked to the phone. They weren't quite sure what I was going to do, and just watched.
The next thing I did was to dial "00" for the international operator. I asked the nice person who answered what the area code was for that city and got the response: 206. Then I thanked her and hung up. Then I dialed 1-206-555-1212 for directory assistance and conveyed my request for "Seattle, Washington, the main switchboard for Boeing, please". I wrote down the answer on a scrap of paper and handed it to one of the guys. They didn't quite know what to say.
None of this was deep magic. Somewhere along the line, possibly by reading 2600, or possibly by digging through the fine print in a phone book, I had discovered 00 for the long-distance operator. Then there was the whole 555-1212 thing which I always found amusing because it was in the middle of a block which was otherwise rendered useless by Hollywood's phony numbers.
I'm guessing that their problem was one of not knowing the area code, not knowing how to get the area code, and even then, they might have known "411 for directory assistance", but had no idea how you'd dial that with an area code in front.
It's always nice when some arcane bit of knowledge can be used to help real people with real problems. It beats theoretical issues any day.