PyGTK Popup menu?

[dataangel]

I want to make a pygtk app that consists completely of a window. When I 
run it, a menu should appear where the mouse cursor is. I've been 
looking at the official pygtk tutorial and documentation, but everything 
seems to assume that I'm either creating a window to put the menu in (I 
just want it to be the menu floating by itself) or that I want a button 
press to trigger the menu appearing (it should just pop into existence 
when I run it).

I've tried just creating some menu items, appending them to a menu and 
then calling menu.popup(None,None,None,0,0) but nothing happens :/