How to display extra navigation options when a primary link is rolled over

I think I'm coming at this as a programmer, which is all wrong.

I've attached a picture of what I'm trying to do. It shows the desired state after the user has rolled over the "BLOGS" primary link.

I've got four primary links (News, Blogs, Culture Projects). When a user rolls over one of these links, I'd like to have the navigation "expand down" and show a block containing the three most recent articles in that category and a block of links. When the user rolls over a different primary link, the expanded navigation content would change. I can get the three blocks of contents in a view easy, as well as the block of sub-menu items at the end.

Can someone point me at the module(s) I should be using to display this extended navigation area and how to fill it? After hours of searching I've found lots of modules that almost do each part.

Any help or suggestions would be greatly appreciated,

--Jason