How to play chess differently (yet another random idea).
Take 2nd board and 2 kings. First board is usual. 2nd board, only 2 kings at their places. Boards are next to each other but not connected. Player have same color on both boards.
To win, do a checkmate on any of the boards.
Turns: during your turn, you could move piece on any of the boards (but only one).
When piece is captured on first board, its owner could place it to any place on nearest 2 rows on 2nd board.
When piece is captured on second board, it is eliminated from the game.
Special rules (castling, en passant, etc) are not allowed on 2nd board.
This is great way to flex you ability to think and make decisions, as advantage on one board may bring huge disadvantage on another.