"Easter Egg" style key combination changes

FROM : Development
DATE : Sun Jan 20 19:21:52 2008

I would like to include a special debug menu in one of my application. 
I do not want this menu easily available, as it might give the average 
end user the ability to do things that would cause support nightmares 
for the application. What I want is to have the menu appear when they 
hold certain keys and click the Application menu, and vanish when they 
let the keys go... I'm having trouble finding information on this and 
honestly I do not even know where to start looking. Any ideas?