4 "Junior Solar Sprint":
For younger students (not even in high school yet), there's a "miniature" version of the Solar Car Challenge. It's called the "Junior Solar Sprint":
The Junior Solar Sprint is a free educational program for students in grades 5-8. Students design, build and race solar powered cars .. but these are small enough to hold in your hand. Each has its own solar panel on top that directly powers a small DC motor. The solar cars are available as complete kits.