To celebrate 70 years of service to Mexico, American is offering double AAdvantage miles on all routes to Mexico between September 4 and November 13, 2012. Registration is required prior to travel using promotion code MX70A, in order to be eligible for double miles.
There are also some fare sales to Mexico, though I don’t see anything that would warrant a mileage run. That being said, if you’re headed to Mexico anyway, might as well rack up double miles!
(Tip of the hat to AAdvantage Geek)