I found an event on the My Trainer Rewards website with the titling: Great Balls, Lucky Eggs and Incense Giveaway!
I believe this is the first instance of the new promo codes being given out.
As stated in the event information, the codes will only work on Android.
The Lure-A-Thon is only in Colorado Springs. The information associated with the Lure-A-Thon can be found here.