I just found an offer sitting in my emails that I had not looked at since it was originally sent to me. Chicago residents can earn 2x American Express Membership Rewards points until November 15, 2011 at the participating merchants simply by enrolling their AMEX card and using it to pay the merchant. This offer originally was from October 1, 2011 to November 15, 2011.
Although, it says that the offer is for first 1,000 card members who successfully I was able to enroll two hours ago. This means that the enrollment is still open and readers can still take advantage of this offer.
Terms and Conditions for the offer as copied and pasted from the offer webpage:
To be eligible for this offer, you must register a Membership Rewards program-enrolled American Express Card at americanexpress.com/getrewardedchicago between September 15, 2011 and November 15, 2011. You may only register one Card for this offer. Using the same registered Card for each transaction, you must make at least one purchase at participating merchants between October 1, 2011 and November 15, 2011. Registration is limited to the first 5000 registrants. You may earn a maximum of 1,000 bonus points during this promotion. Prepaid and corporate cards, and ExpressPay transactions are not eligible. If your Card is replaced during the promotional period, please call the customer service number on the back of your Card for assistance. Bonus points will be credited to your Program account within 10-12 weeks after charges appear on your billing statement. Some American Express Cards are not eligible for enrollment in the Program. Program terms and conditions apply; see membershiprewards.com/terms or call 1-800-AXP-EARN (287-3276). Participating partners and available rewards are subject to change at any time. Bonus ID 6966. Additional terms apply. See Registration Terms & Conditions for details.