Tennis scoring macro

Hi,

This is a bit of a tricky one but....

I want to basically have two buttons in excel - for example - Player A and Player B. I would like to be able to click these buttons and then depending on the number of clicks it allocates a score to another cell. Example, one click on Player A gives a score of 15, another click and it changes to 30 etc etc.
I would like to use this for a complete game of tennis so once we reach the end of one game both scores resort back to 0 and the number of games changes from 1 to 0 etc etc, and then include the set scores.

Any help would be appreciated.

David.