Materials: one 6'15" sheet of good plywood, 2 6 foot 2x9s, 3 12 inch 2x9s, some screws and a screwdriver (electric kind), one 6 foot piece of angle metal
How to build it: Take the plywood and the 2 6 foot 2x9s and have someone hold the 2x9s in place with the plywood on top so that it will kinda look like a grind box and put some screws in to get it put together. You have just made the sides.
After you get the sides put on you will need to get the ends and the middle piece in. Take the 3 12 inch 2x9s and put two at the end and one in the middle so that they are toughing the plywood and are in between the side pieces.
Now you need to drill some beviled holes at the the ends and the middle of angle metal. Make sure you drill them on the edge so your trucks won't catch if any of the screws stick up above the metal. Take some screws and drill them into the holes. Make sure that someone holds the metal tightly on the box to that it won't be a piece of shit.
Put a little wax on the metal and do some stuff on it and be happy or something. I'll be getting real pics for this soon.