I noticed this promotion logging into my Discover More Card this morning.
Earn 2% CashBack Bonus on purchases made at grocery stores from 6/29/12 (or the date on which you signed up, whichever is later) through 7/1/12. Grocery store and purchases are those made at merchants classified as stand-alone grocery stores or supermarkets. If a purchase is coded for a category other than those listed above, it will not qualify. Grocery or food purchases made at convenience stores, gas stations, warehouse clubs, supercenters and discount stores are not eligible. Purchases earning 2% CashBack Bonus will not count towards your total annual purchases to determine your tier level. Rewards are added to your CashBack Bonus account at the end of each billing period. See CashBack Bonus Program Terms and Conditions for further details about your reward program.