If you thought things were getting old school last week, check this out. I present to you: Nethack and Xenocide.
If you run Linux and don't know about Nethack by now, you're a minority to say the least. This game is damn popular, so damn popular that if I were to write a Linux RPG roundup and not include it, I'd be killed. The greatest thing about writing about Nethack is that even I have enough artistic skill to reproduce the game's characters almost exactly. For example, your main character: "@", or your little dog: "d" or a big, scary dragon: "D". Yeah, it's all ASCII text, bitches. As you'd imagine, with nothing to fall back on graphically this title has to make it's mark with pure gameplay, and it does it pretty well. If I were to sit here and describe everything this game has in it's bag of tricks, you'd be bored to death. I would as well, so I'll leave it at this: I don't play "rogue-likes" (which is the category Nethack would fall into), but I do play Nethack. Give it a go, it runs on almost anything and it fits on a floppy.
Xenocide is also a rogue-like, although unlike Nethack's fantasy vibe, Xenocide has more of a sci-fi feel. Maybe that's just because Xenocide explicitly tells you the first level is supposed to be a space shuttle, I can't really tell the difference between a "#" and a "# in space". Xenocide is also a lot tougher right off the bat then Nethack is; I can't count how many times I was killed by a Rabid Prankster in the first couple minutes of playing. Now the downside: there is no story to speak of(yet) so it's pretty much fighting all manors of "r", "w", and "m" monsters until you get bored and stop. Like I just did here, except with writing.