Country programming contest, soon.

Hello fellow DIC members,

There is programming contest in my country soon. Therefore I need to send like homework project to them, so they can decide if I am going to present my project or not. I am programming in C# currently, and I need some unique idea for homework. Something that's not too mainstream, something that I would show off my skills with, and something that would impress them. I would rank my C# skills as INTERMEDIATE, I am not EXPERT but I am not BEGINNER as well.
So I would like to ask you my fellow DIC members,
What should I do as homework project?
This is really important contest for me, and I would appreciate every single reply here.

Thanks again.

Have a nice day,
Bozzy.