Back in the days, I figured that Nethack would be too obvious so I went for MUDs (online multiplayer text adventure) instead. Except you need to connect somewhere in order to play. Hopefully, I had a device on which I could randomize the MAC address and IP, so if someone was monitoring outgoing connections they could have a harder time to figure out who it was.
I didn't do that long enough to really put it to the test, though. Eventually I switched to working on side projects instead, which look similar to what I was normally doing. And worst case scenario, I could argue that it is for training or something, which wouldn't entirely be a lie.
He was not happy.