I present to you one of my very first Gosu games, WhirlyGigs. I made it a few months ago but forgot to publish it :P
The original version was written (by me) in a small step-up to programming... thing called Scratch. Link: http://scratch.mit.edu/projects/Jwosty/900352
In it, there are three bodies: the red one (the largest), the orange one, and finally, the yellow one (the smallest). Each orbits around another at the given speeds (changed with the sliders at the bottom of the window). The red goes around the center of the screen, orange goes around the red, and the orange is followed by yellow. The yellow circle draws a path, following where it has been. Space to reset orbits/clear pen marks, and the sliders are color coded to match the circle who's speed it modifies.
The source and wrapped versions (currently only wrapped for Mac) are attached.
Oh, and have fun!
***It would be appreciated if someone would post a Windows wrapped version; if this happens, I will add it to the topic post.***
Currently, the grip can be dragged outside it's slider. I'm working on fixing this little by little; probably won't be fixed for a while.