Mousetrap cars are fun to build and race.  They are a great way to explore science concepts like energy transfer, friction, torque and intertia and they make a great youth STEM project for the classroom, 4-H or other youth club. 

Building a mousetrap car is relatively simple and only requires some common materials found around the home or local hardware store.  Below are some downloadable activity resouces on building mousetrap cars, modifying them for a distance contest and some of the basic science of mousetrap cars. 

• How to Build a Mousetrap Car
• How to Modify a Car to Make It Go Farther
• Some Basic Science of Mousetrap Cars

For an online tutorial and video view this Build a Mousetrap Car Instructable.