If you're good at RedPower2 then I sugest you doing something that I've been working on of late, a space-ship! Using frames, motors, logic gates and maybe even a computer, you can build what is known as an inch-worm drive that can move the entire structor almost anywhere! It is a slow, inefficient method of travel that is hard to build and a fantastic monument to science! And if you are clever enough you can build more stuff on it!