This is a really small ELO rating system for our table tennis matches in the
office.

It takes the basics from the ELO system but the number of points gained or lost
for each match is not only determined by the outcome of the game. We take into 
account the result of the game to determine the new rating. 

For example if player A and player B have both an ELO rating of 1500 and player
A wins wins 21 - 0 he will win 16 points, however winning 21 - 19 will only give
him 5.33 points.

This makes the game more fun giving bad players a motivation to play against the
strongest ones, even if they lost they might win points against high ranked 
players if they perform well.