Game Room

For this and the other challenge achievements, you can use another account on your xbox if you have one. A silver account will do. You do have to buy a game to be able to send challenges. But once you do, set it to an hour, most points, fail miserably on the second account, beat that score with your main, and voila, you won a challenge!

Obviously sending yourself requests from another account to your main account is the easiest solution. A silver x-box account will suffice.
Make sure the settings are as follows:
Challenge Terms: Highest Score
Number of Tries: 1
and
Friend: Select your main account that you wish to obtain this acheivement on OBVIOUSLY.
The rest of the settings don't really matter as long as you make sure you only have 1 try set.

Games I find easiest are ones that you can fail on fairly quickly such as Crystal Castles.
If you have the game set to highest points then simply run into the enemies until you're completely down and out on your side account then on your main account beat the challenge set!
Obviously there are plenty of games you can kill yourself on swiftly...(LOL)
Send 20 challenges with your side account and beat them all with your main account and you're done here!
AWESOME!

In order to earn this one, you're going to have to need to purchase at least one game for your arcade. Once you do that, you can create challenges for that game against your friends.

Boosting is easy. You can have several challenges running at once. Your friends can also challenge you in return. Set the challenge to the shortest time possible, and win a token amount of points. Have your friend play the game and do worse. Voila! Challenge won. Win 10, and you'll get this shiny, then you can help your friend boost as well.

There is an even faster way to do the above boosting methods with a silver account (or any second account). It is not necessary to play the full challenge time. The account that is losing the challenge can accept the challenge and immediately quit. The losing score will be 0. The account that is wining the challenge can set a score greater than 0 and then immediately quit. For example, in Astrosmash, shoot one asteroid and quit the challenge with a high score of 10. Each challenge only lasts about 5 seconds.