In France we have "Marseilles' chess". The players play two moves in a row at each of their turns, except for the first white move, but otherwise the rules are the same. If you put the enemy king in check at your first half-move you pass the second ; if you are in check you must go out of it in the first half-move, it is forbidden to get in check in the first half-move as well. Alekhine had played a few games of it. Beware, it is highly tactical.
I have also seen in Hungary many chessboards for three players such as this one (link), but never played it.
can we please have some varations of chess?
such as crazyhouse or bughouse? I don't care much for atomic or suicide or losers. but crazyhouse is fun.