■ 🕑 2. 
   Do Nethack or DC:SS count? I love both of those games, even if 
   they're... "lacking"... in modern sensibilities. 
   
   Probably the FOSS games I play the most are Tetris in emacs and Gikopoi:
   and someone's working on making a Gikopoi client for emacs, written in
   emacs lisp, which is uhhh pretty unexpected?????? 
   
   I kind of want to write a server for traditional games like cribbage in
   C and then make a client in emacs-lisp but I worry I'd never be able to
   find friends to play those trad games with ;_; Just a websearch for 
   "backgammon emacs" is depressing enough as-is, (zero results), why 
   bother writing several hundreds or thousands of lines of code to sit 
   waiting in a lobby to play a game with no one.... ;_;
   
   It's not FLOSS by any means, but one of my favorite "free" online games
   is Power Bomberman: 
   http://www.bombermanboard.com/viewtopic.php?t=1925&start=760
   
   Definitely will check out cataclysm:dda later, thanks for the rec OP