I actually like this one:
There are five pirates in a ship and they have found 100 coins.
The biggest pirate offers a way to divide the coins. If at least half of them agree on the division, it will be done. If not, they will drop him into sea and the next biggest pirate will make an offer.
What is the number of maximum coins that the first one (the biggest) can get?
The pirates first like to live, then money, then killing each other, but most of all they believe in democracy!