A little game with the same principles as the same-named tv-show.  
The idea is that you have 26 cases with different amounts of money in it. You start by choosing your case, the money in it is now yours - but you don't know how much it is.

Every round you open now a few of the other cases and narrow this way the money in your own down. And after ever round the "banker" offers you a price to buy your case.  
Its then your descision if you accept the deal or not. It's your descision how much you will risk to get as much money as possible.