Bughouse is an interesting type of chess where four players, two per team, play chess on two boards. When one member of a team takes a piece, his partner gets to drop that piece on his own board.
I know a lot of you know this, and I know bughouse chess has been suggested to Fencer.
Maybe we can have a variation on this, where only two opponents play (without teams), yet the players play simultaneously on two boards. The boards can be shown on the same screen. When a piece is taken off of one board, it can be dropped on the other board.
I had an idea for a chess variant tonight. It would be called something like slide-rule chess. One horizontal row in a regular chess game would randomly slide one space to the right or left, with all the pieces on them, after every move.