A game/zen simulation originally written by Leonard Richardson (of segfault.org) for DOS. Recently ported to GNU/Linux and other POSIX/ncurses compatible systems. Web page at http://www.robotfindskitten.org .

Quoting almost directly from the robotfindskitten Debian GNU/Linux (also rumoured to work on FreeBSD and other reasonably compatible OSen) intro text:

"In this game, you are robot (#). Your job is to find kitten. This task is complicated by the existance of various things which are not kitten. Robot must touch items to determine if they are kitten or not. The game ends when robotfindskitten."

Actually playing the game is funny as hell at first, boring the second, third, fourth, fifth and Nth time and enlightening the last time.