Hi, folks - I took part in Ludum Dare 50 a little bit ago, and I was able to complete a whole game in 48 hours. The theme was "Delaying the Inevitable," so I made a game where you're eventually overrun by a bunch of mammoths.
The game plays like a deckbuilding boardgame, although it's single-player. There are a bunch of special "power moves" that you can purchase, and you get to use a few of those (randomly selected) each turn, along with some basic moves.
The game did OK in the competition. It was hampered a little bit by speed issues (it's a browser game and I may have gotten too ambitious as to what the browser and my graphics library could handle).
To see the competition page (with more description of the game) see here: Ludum Dare Site
To play the game, check out http://planktongames.com/ld50
My Plankton Games site may go down for a bit over the next few days because I'm changing hosting, but it should be back up within a week or so.