Secondly, the answer to last week's truly horrible question with the sphere and the drill.
The point is that the answer does not depend on the sphere's diameter.Don't shoot me, I'm only the messenger!
Start with sphere larger than 6" diameter, where it's easy to drill the hole but hard to compute the remaining volume.
Reduce the sphere's size; the hole's diameter shrinks, and the remaining volume gets close to the original volume.
When you get down to exactly 6" diameter, the hole has vanished, and the remaining volume is easy to calculate.
It's precisely the original volume: [4/3]pi*[3in]**3 = 36 pi cu in.
How about something a little simpler? The rather addictive bomberman. I downloaded the best version ever the other night (Atomic Bomberman), and haven't stop playing it since.