Hi Mr Burger or can I call you Beef?

I want to make my joystick into a rotary so i can play the second best game in the world, Ikari Warrior (my lawyers have asked me to point out that Ikari Warrior may not be universally recognised as the second best game in the world...........yet).
I saw a thread that i can no longer rember showing how to make a rotary stick from the parts of a mechanical mouse. Due to my frankly laughable attemps to track down said variety of mouse, i'm trying to think of another way.
I don't know how the pot thingy works i just wondered if anybody else did.
I suppose i could build it and take it to work, that would have big, surly Barry the I.T. man scratching his fat miserable head.
Thanks gang.
Voodoo Ray.