C# how to make my GUI box grow in length.

Question

What im trying to do is alot like the menu in this video http://www.youtube.com/watch?v=JGrEgColc_0

The only difference is that my menu would be growing downward, but all im trying to do is get this same effect that was in this menu. I know the menu in the vid was made with C++, but since C# is a lot like C++ I thought this might be possible.





Im working with this game development program called unity....it is able to process many languages including......

C#, javascript/uniscript, boo, and lua