The event offers you a pointer to the object.
One of them is 'me' and the other is 'you'.
To find out which pointer you get in a certain case, you have to read the manual about events carefully!

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt