well, i've got an idea for multiplayer roguelikes (it's not my own btw, read it somewhere):
you use an engine with ticks, and every time a certain amount of ticks have passed, you get to take an action. ticks are based on a timer. say there are 10 ticks to a second, and a player can take a certain action after the required amount of ticks have passed:
moving 1 pace costs 10 ticks, shooting a pistol costs 5, reloading a rocket launchers costs 25 (just example figures)
if you want to move (or shoot etc), the engine checks when you have last done an action.. if 10 or more ticks have passed since your last action, you move. same goes for all the enemies you have to fight, and for your co-players. You could also stack a lot of commands, by pressing left 5 times rapidly, then watch yourself go left everytime 10 ticks have passed, untill the command buffer is empty. probably not a good idea to make the command buffer very big though, so you don't walk into a wall 300 times untill you're allowed to do something else >.<
however, i know that writing something like that means actually writing a completely new game engine. so it's probably not gonna happen here :S