Have your students attach Voyager to a Speedway Wonder™ car, set up a Speedway track of their own design, and they will be ready to challenge one another in a unique way. The main idea is to collect angular velocity data while Voyager circuits the track. Then by carefully studying the angular velocity graphs produced, determine posible layouts of the track. A magnet at one location along the track, coupled with simultaneously measuring magnetic field, allows quick identification of the start and end of a circuit on the track. (Note that an easier challenge would be for students to match graphs with corresponding pictures of the layouts.)
Here is an example track layout. The top graph on the iPad is magnetic field, with each blip indicating that Voyager is passing the magnet. The bottom graph is the angular velocity versus time graph. You might find that simpler designs (i.e., square, rectangle, etc.) would be best for students initially as they learn how to "read" the angular velocity graphs. Then they can make more complex designs for fellow students to determine possible layouts.
Here is the Excel graph for the above layout. It was constructed from the PocketLab app csv file.