Making a stand-alone version of the game
Blender allows you to create a stand-alone version of your game to distribute to colleagues, without them having to have Blender installed. Your game will automatically run when the program is run.
In Blender, select File -> Save Runtime.
The image above is not up-to-date. In Blender 2.48, the option is: File -> Save Game As Runtime.
In the Save screen, enter a name for the game executable (for example ball_game). This will create a ball_game executable in that folder, which you can distribute to your friends.
You may need to include a few other files along with that executable. Copy the file to a new folder and run it. If it gives an error that a file is missing, copy that file (probably a .dll file) into the same folder. Continue this process until the game runs. You will then be able to distribute those files to your colleagues. You may want to refer to this short document if you have dll errors: http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Making_exe .