Comparing Numbers - A Silly Little Game

Today my class compared numbers up into the millions.  I think it's amazing how 4th graders think it's such a big deal to work with numbers in the millions.  Maybe they believe it because I relate millions to money - though I've never been close to a million dollars in my life...  
Anyhow, we compared... and compared some more... and then I told them that we were going to play a game.  Of course this is the first official math game of the year, so they got all excited about the possibilities.  Then I told them that one person would win each round, and they got even more excited.  
They all wanted to win.  
So with a partner they took 2 whiteboards (they each have their own whiteboard), and they had to draw 7 place value spots on it - complete with the commas in the correct place.  
___ , ___ ___ ___ , ___ ___ ___
Then they had to each hide their boards and write a number on those little lines that they thought might win the contest.  For each round they had to both be ready to share, they put down their boards so they could both see, and had to compare the 2 numbers.
Some rounds I told them they had to find the greatest number between the 2, and that person won the round - the winner put a little star on the top of their whiteboard.  
Other rounds I called out that the lesser number would win the round - and the person would win.
They worked together and they had fun.
The best part for me?  Other than them reviewing the concept was there was NO PREP involved!
So tomorrow we will be ordering numbers and guess what?  We will be playing it again in groups of 3.  At least I know they will have fun!