I'm hoping the pictures are clear enough that you can build the ball solely from them but I have included text on each step just incase you get stuck. If you can understand the step just by the picture then you're pretty awesome and should just ignore whatever I wrote.
A short video showing the roundness of the ball. More exciting video coming soon.
Step 1: Parts
I'm including a parts list of the parts I used in this Instructable so that it will be easier to understand. Of course you can always substitute for parts that you don't have with ones that you do (like using two 2x4s in place of the 4x4 or using two 2x4s in place of the 2x8) but just be cautious about maintaining structural integrity. I know rainbow warrior (using bricks in any and all colors) is sometimes the only option but the shape of the ball shows up better in solid color so if possible, try to stick to just one color.
-8 1x4 bricks with knobs