OK - but in that case, just about everything involving CSS could be termed a cheat!
The items are AP (Absolute Positioning) divs, which are set to be relative - i.e. relative to their containing element. (Try selecting one, and change the positioning to 'absolute' and watch the items collapse to absolute top-left). It is up to the containing element to position its contents.
And yes, it is possible to centre a CSS Menu on the page, as previously described.
Are actually having problems with the way your page looks?