My latest idea for a game that will likely not make it off the ground:
A turn-based arena combat game using the Chainmail Man-to-Man and Fantasy Supplement rules.
Players would make teams using the Chainmail point system, consisting mostly of creatures (but if they want to throw in a mess of human footmen or whatever, sure, why not?), and have their warbands duke it out in large arena spaces.
Arenas would have various types of terrain including things like traps and lava, and some would have goals like capture the flag (or magic sword), eliminate the enemy commander, etc. to spice things up a bit.
I would probably have some player vs player combat as well as player vs DM combat involved.
And I'd probably come up with a roster of heroes, super-heroes, anti-heroes, wizards and dragons that would be unique. Once recruited they're no longer available unless the team manager (player) lets them go. And if killed, they're gone, out of the game for good.
For victories, players would receive gold which they could use to hire new troops. Win or lose, players would gain XP, and levels would determine the maximum number of points they could spend on their warband.
I'd likely run this play-by-post so there would be ample time to review orders and results each round.