I saw the same kind-of menu on another site only it had been done entirely in a table with the most god-horrid javascript I've seen in a while, therefore I decided to recreate it (semantically).
A more interesting variant of the original vertical menu, this one is hidden (hover to open the menu). As always, these things don't work with Internet Explorer so I had to make one little CSS hack for IE to even show the menu (otherwise it would stay hidden).
This, of course, is a slight horizontal variation of the menu above (it's kind-of buggy, though).