Here's an example of something random I did with GDI in C# a while back:
It doesn't need to even be a control. Just see what you can draw. This one I did was animated, and it draws a spiral outwards. To create the positioning, I used some math involving the golden ratio.
I even created a simulated pong game in GDI a few months ago:
I've made graphing controls, buttons, textbox controls and many others as well. It's more of a creativity thing though after you know what you're doing.