This is in our "Star" event quests today:
http://farm3.staticflickr.com/2853/1...60d7710b_o.png
Accepting it gives you a 30% off coupon that expires in adayhour.
Not a word about it in either Update Notes or Event list. No idea how long you have to claim the coupon, or what the rest of the event (if there is any) offers.