Around 15 years ago I played for the first time Nethack. I should have been working on my MA thesis in medieval ecclesiastical history but I probably spent a lot more time online: reading the newsgroups, chatting in the IRC or in the university's internal bulleting board known as Portacom.
Sometimes I even played games on the Unix system. There were not too many games installed, but there were many online multiuser dungeon games I was able to play over telnet. And the famous Adventure was available and of course the Nethack.
I was never completely hooked on Nethack, but I completely understand those geeks who spent the nights hacking monsters in the darkness of the dungeons. Sometimes I have even tried to play Nethack with my Linux systems. It certainly is not for everyone, but it is one of the few playable games available for the Linux console.
Even if you might not fully understand the magic of Nethack it is certainly worth installing in the Linux system. If you are desperate enough you might even like to start killing the monsters in the deep dungeons!