It's really simple, in a lot of multiplayer games such as Castle Crashers, before everyone starts they have to push A to show that they're ready. It would be a nice option for game masters to be able to make this sort of check with their players to know when the game can start, or when to resume, or it could even serve as an ingame function. The GM could hit a button somewhere or even type a command, and a prompt could open to the players, or it could just enable the "ready check mode" or something. I like the idea of being able to toggle this mode, and it says something in the chat log or somewhere on the screen to notify the players of it. Then maybe the players could click on their own avatar or namebox, and a green box could wrap around it to show that they're ready to go. Of course, the GM should be able to clear the check or reset the mode to normal at any point. Maybe it could push a prompt to the screen and grey everything else out with options the GM can write in themselves? There's a lot of possibilities on how it could be implemented, and if it was extended a bit, it could be used for voting purposes, and maybe even more creative uses. I for one would find a lot of use out of it. I don't think anyone has suggested this already?