In the event that I'm losing, then I can declare my king is a super king which can teleport to any square on the board. Which means that since I can move it anywhere, my opponent is in constant checkmate! 
Of course, it only works for me and not my opponent!
If You Have the Chance.....
Sort:
Hyperspace properties on the i-file.
Appeals:
If the fielders believe a batsman is out, they may ask the umpire "How's That?", commonly shouted emphatically with arms raised, before the next ball is bowled. The umpire then decides whether the batsman is out. Strictly speaking, the fielding side must appeal for all dismissals, including obvious ones such as bowled. However, a batsman who is obviously out will normally leave the pitch without waiting for an appeal or a decision from the umpire.
My wife loves touch move...
-The goal of the game is changed to marching the king to the otherside. The first to do it wins.
Oh, that is already an official rule, sorry 
I would rule that on its first move a pawn could move back either diagonally or vertically into square vacated by a piece... this could improve defensive possibilities.
A draw is considered a loss for White.
wouldnt it be fun if u have 2 kings to defend and if one would be checkedmate...u lose..?
You're allowed to skip your turn. In that case you couldn't be mated with K+R vs K.
When prommoting a pawn - if the opponent does not say what peice he wants exactly 0.1432658356754 seconds after putting it down then I get to promote a pawn - even if I have none.
* Rule only applies if you are called TheProfessor on Chess.com*
Just like I said.... If you have the chance to make a new rule or change a rule in chess .... what would it be...?
Example :
"The King can't castle until the 50th move......" or
"The King can now move outside the board....."
but it's up to you if you think of something *ridiculous* well... uhm..... let us know....