Twitch, the streaming service for gamers, has started a neat little social experiment, in which no less that 40,000 players simultaneously play the same Pokemon game. Players give commands to the character via entries in the chat.
As a base of the experiment, Twitch uses the gameboy version of the Pokemon Red game (151 romhack) running over an emulator. The game also uses an IRC bot which parses commands from the adjoining chat window and transfer them to the game.
If you want to issue commands, all you have to do is write left, right, up, A,B in the chat while the game character converts those commands. Due to the nature of the Twitch streaming network you should expect some lags and these are anywhere between 20 to 40 seconds.
If you want to check out how a game of Pokemon with 40,000 players look like then you should check out the link below.