Many nights were spent on party lines
Party Line or Hot line is when you have more then one line on an automatic message. If the message was low enough then the people could hear each other. The messages could be "You have reached a nonworking number" or "This line is out of service, please hang up and try again". Because the voice of other people was so low you had to shout very loud, some phone phreakes used amplifiers to make their voice clearer. Others would play music, much to the annoyance of others. On rare occations the message stopped because of a malfunction, making that party line very popular in that particular city.
A service line called loop arounds was an alternative to regular party lines that had the added benefit of not having any automatic message.
You could be completely anonymous on party lines, in a way they were the social networking for young people at that time.