Thriller Fan, if one side has two kings, you should be able to take a king then if possible, only having to checkmate the one left standing. After all, the whole idea of checkmate rather than taking the king was that it represented a position of inevitability. If only one king is mated though, things aren't so inevitable since one of them is disposable.
Also, to verybadbishop, although the bishop is pinned, surely it would be happy to capture the white king, as it is a king after all.
I like Abhishek's idea. To add to the idea, a piece not only can't land on a poison square without dying, but it can't move through it either. That could be a nuisance for long range pieces.
Maybe there could be some way to implement a system that allowed you to poison squares (or your own pieces possibly). Perhaps even make a new chess piece for that purpose.
Remove the stalemate rule.
Abolish the "win on time" rule if the material advantage is a rook or more. A draw is to be declared instead.
" Oh mandy..when you came and you gave without taking...but i sent you away..oh..mandy..and i neeeeeed yooooooouuu." 
Wow!
50 move win:
If you survive 50 moves in the game, you have the right to knock down your opponent's king and say "You forfited" .
if you win the opponent gives you cafe latte.. if you lose you pay for your own latte
After the first check the first one who blinks loses.
winerkleiner wrote:
After the first check the first one who blinks loses.
everytime you take a piece, you gain control of that piece and you would place it adjacent to your king, if there is no empty adjacent square, you can save it off to the side for when you have an empty space.
Whenever a piece is captured, that piece is tossed in the air, whomever catches it, gets to place it anywhere.
The one that I've proposed before is that you can promote to King if you want. If you do, you are allowed to leave one of your two kings in check, but never both. To lose, BOTH of your King's must be checkmated at the same time.
Therefore, if I promote to King, and I have a King on a8 and another on g1, Black goes Qb8 (with his Knight on d7, protecting the Queen), then in essence, that King is checkmated, but my other one isn't, and if he moves the Queen off, the a8-king is back to life. If I say, trade Queens on b8, I get him out of checkmate, so promoting to King is going to make winning for your opponent EXTREMELY difficult, but you may also have trouble mating your opponent with an extra King, whereas an Extra Queen will likely kill him. If you are about to promote, but so is your opponent, and you promote to Queen, he may decide to promote to King. You have an extra Queen, he has an extra King you have to mate!.
Adds a twist to decision making, and definitely adds to the value of promoting a pawn!
Imagine this stalemate after 2 promotions to King by White: BKa5, WKb7, WKc4, WKa3
I love it!!
Gravitational Acceleration - When a piece is captured on a square, all empty squares in its 3x3 grid get filled by pieces from its 4x4 grid. And the pieces moved in are the choice of the capturer.
Here's one: If you tinker with the rules it's no longer chess that you're playing.
Win if you capture all opponent pieces. Its war!
Win if you capture all opponent pieces. Its war!
That was an actual rule once:
http://en.wikipedia.org/wiki/Lone_king
Eliminator - Every 7 material points you capture of your opponent, the bottom rank gets neatly eliminated with its pieces.
Then it can be iplemented and very sound rule
macer75 wrote:
chessfansupporter wrote:
Win if you capture all opponent pieces. Its war!
That was an actual rule once:
http://en.wikipedia.org/wiki/Lone_king
I have a friend that would play "ninja chess," wherein all rules of chess were the same, except that each player would write a small "N" on the bottom of one of their pawns.
In addition to it's normal movement, that pawn can move and capture as a Knight, but cannot promote. Neither player knows where the other player's "ninja" pawn is, until it moves likes a Knight.
I thought it was stupid, but he liked the idea.