Displaying a 2nd Tier category menu in header?

I'm trying to find a way to display a second category menu (on select pages) of second tier categories? And highlighting categories.

Example: The top tier categories are DVDs, Books and Games. If someone clicks on Games I want a second top menu to pop up under Games which lists (as an example) Xbox 360, Wii U and PlayStation 3. A person can then hover over those fora drop down of their sub-categories.

If a customer clicks on Games I want it to stay highlighted when on the page.

Any suggestions?

http://www.opencart.com/index.php?route ... 20category