Tilt ball maze.

A small maze that is enjoyable. It is complicated to get from one side of the maze to the other and back. A nice fun challenge. All you need is one rubber band.
You might need to glue the under axis together.
The ball for the maze is one fourth of an inch, or 12. 7 millimeters, you can use the 3d file, or it can be swapped out for a ball bearing of the same size.

Print instructions

Support on the two mazes recommended.