Also,
The Ball is cheapy cheaps on Steam. I saw it originally for £15, and thought, "No, not for a mod", then a demo came out, and I played it and it was awesome, and now it's £7.50 on Steam. Which is totally worth it.
HOWEVER! You can get it even cheaper!
SavyGamer shows how you can get it for
£6.58, straight from the developers (more money to them), AND it activates on Steam! Which is awesome. And well worth it.
Edit - Might not activate on Steam, actually... But still worth it!