I found a link to this from a blogger (Ashley) who posted a question to the Yahoo Blogger Help Forum (Here ).

If you click http://mysticalball.com/ or the link above it will open the site in a new window.

I won’t spoil it for those who don’t know how it works yet, but if you are interested, I’ll probably make a new post revealing all.
It is not as difficult as you think… I’ll delay any commenters posting the solution for a while just in case you post and wonder why it never appeared. Can’t be spoiling peoples fun just yet.

And no, it doesn’t install a key logger on your machine, it doesn’t use your webcam to see which ones you are looking at, and no it doesn’t rely on you holding the mouse of the number you will choose. Shout out to someone else in the room to pick a number for you, and then you do the maths 😉
It will still work.