World Cake
My daughter received a mission call and before opening it I made this world cake.  When people came to the call opening party we had them put a number on a little yellow flag and then on a separate paper write their number, name and guess where she was going.  The cake was covered with little yellow flags.  The winner of the closest guess received a bag of m&m's and my daughter got to eat the piece of cake where her LDS mission call was to.  It was a lot of fun.

Hint: To decorate the cake, I printed a simple outline of the world off Google maps and cut it out.  I laid it on the plain cake and put the blue frosting around it and even on top of the edges. Then I removed the paper and carefully put the brown in the middle to make land masses.  I had a separate printed map with detail for people to see where countries were.