As we all know, Lego turns 50 this year and to celebrate they've produced a bunch of "gold" bricks as a free gift with purchase of over $50.
The new set, "Town Plan" also includes three 2 by 2 golden bricks as well as a letter from company owner Kjeld Kirk Kristiansen, who appeared on the original town plan box when he was much younger and returns on this one. 
They've also produced a nice little anniversary site with a historical overview of their products.