I actually thought that the 20/20 referred to eyesight.
But please continue explaining the rules. I've always wondered how to play cricket. I have a few questions about the rules you've already posted, though:
1) Why are 20 overs more entertaining than 50 overs? Is it because the game drags out for too long otherwise? And why do you call it oneday cricket, do some cricket matches last more than a day?
2) What's a run? Is it like a point?
3) What's the rope you're referring to? Is it the same thing as the boundary on the diagram?
4) What are the sticks in the ground for, and why are there three of them? I've always wanted to know that.
I hope I don't come off as a complete moron, but I've never seen a cricket match, and I don't believe it's played anywhere around here, if it's played in Denmark at all.