"When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty-one, I was astonished at how much he had learned in seven years."
The most fun thing I did with it was to write a "war dialer" inspired by the 1983 movie "War Games".
It had a "graphical" screen where one could enter a telephone area code, an exchange, and starting and ending numbers, then it would command the modem to dial each number in sequence.
It would log the call results as "no answer", "busy", "voice", or "data".
Nice work