How to Create a Drop Down Menu Like On Tuts Plus

I am wondering if anyone knows of a tutorial on how to create a drop-down menu like the ‘How-To Tutorials’ menu on tutsplus? There is a similar drop-down menu on Khan Academy (i.e., the Subjects menu).

In particular, when you hover over an element on the left-hand side, a right-hand side menu open up with a different background color and links, etc.

I am trying to figure out how to create such a menu. Any ideas, tips or tutorials to suggest?


I think this can get you started.