Another Facebook deal!
AAdvantage on FB and play their Mystery Miles game. It consists of entering your mileage number and that's it.
You will win at least 100 miles, but could win up to 100,000! I won 100 miles, my sister won 200.
I'd do this right away because in the time it took me to write this post they have gained over 1,000 "likes" so I'm not sure how long the game will run.
Note: Anytime you add or subtract your miles from your AA account you extend it for another 18 months. If you don't have any activity in 18 months it cancels all miles, so this is a good way to reset the counter!