Originally Posted by o H i T M a N z
Running the Show - 30
You dominated a friend in Challenge mode
To unlock this achievement you have to gained a +10 in your tally over your friend. You will have to beat 10 challenges in a row against the same person. This can be easily obtained by having a friend send you very easy challenges to beat, but its always better to just dominate your friend beating his best scores.
Just thought I would add this.
If you don't have a friend who has played the game and can't find someone to help you, you can use a silver account on the same xbox. Just send a challenge from the dummy account to your real account and beat it 10 times, the same as you would with a friend.