I used Tinkercad to create a 3d printed case that holds the light pipe and the servos in place above the Circuit Playground and Crickit.  

This case has space for 4 micro servos to attach around the edges, but we'll only be using 2 for this project.  The AA batteries are just not sufficient to run 4 servos (I sure tried!), but for projects that plug in or use a larger power source, the spaces are available.

It also has optional buttons that extend through the case, if you want to use Circuit Playground's onboard buttons to control your project.  For this project, I'm not using the buttons so I just left them out.

The holes for the light pipe are for 2.5mm - 3mm light pipe.  Be sure to edit the project to change the size of the holes if your light pipe is a different diameter.  If they a-l-m-o-s-t fit, you can use an awl to widen the holes a bit after it's printed.

I printed in green PLA.  If you print upside-down (with the top of the case on the print bed) then you don't need supports.  It may not look as pretty when it's done, but for my project I can't see the top of the case anyway since it's covered in snakes n'things.

If you don't have a 3d printer

Look online for 3D printing services like Shapeways.com.  You can often send the model to one of these services and they'll mail you back a perfect print.