This is a lasercut model I designed of a down hill racing cart I became aware of recently.

Using a design centered on an orange crate, teams build cars and then race them on a straight, downhill stretch. The result is lots of kids and their families constructing racers and having lots of fun together. While there are several such events, I visited the Orange Crate Derby which has been creating joy for 35 years. http://orangecratederby.com

Constructing your Orange Crate Derby car is pretty straight forward.

Modify the Design:
Included with this post are two files, a DXF and a Corel Draw. Either of these can be downloaded and edited with appropriate software. I'd encourage you to make it your own with changes you'd like to see but if you just want to try an assembly then you can likely use the DXF with your laser CAM program.

Cut your Wood:
Without wheels, the body of the car is 130x30x30mm and all the cuts can come from a 200x300mm piece of wood. I designed this around 3mm ply so that's what works with all the slots. You should know your speed and power settings for this material on your laser.

Assemble your Car:
From the pictures you should be able to piece it together. The only thing that's not obvious is the axle structure on which the wheels are mounted. Those are made from gluing together the three long pieces that are cut from the orange crate. You'll find that the middle of each set of three slats has slits cut in it. That was designed to accept small nails so that the wheels can spin but I never actually implemented functioning wheels. Please do!

That's it, just sit back and wait for your glue to harden.