This is an in-progress JRuby port of notch's 48 hour "Ludum Dare" game competition entry, Prelude of the Chambered.
Notch's Java code is pretty straightforward and I've been looking for an excuse to do a "real" project in JRuby for ages. This seemed an ideal opportunity.
Porting is still in progress but the first few minutes of the game are playable, to a point. Doors don't seem to animate properly but you can go through them once opened, nonetheless.
Controls are W, A, S, D and space. Or arrow keys. To get started, turn around and punch the "broken" wall. Best place to head is along the corridor, to the left, and down into the dungeon. You'll find boulders to punch, magic gloves, and bats to kill down there.
To run this code, get JRuby installed (rvm install jruby?) and then just run (from the root folder):
Prelude of the Chambered is a game by Markus "Notch" Persson and Mojang
This JRuby port is by Peter Cooper
Unsure as yet, not sure of the license for the original game.