Get 2X Membership Rewards points each time you use your enrolled Card to make a purchase on your Lyft mobile app by 12/31/2016.
Seems to be available on all MR earning credit cards, at least for me.
ELIGIBLE PURCHASES: Valid only on Lyft mobile app transactions made in the US. Excludes all business transactions and Lyft line purchases. Purchases may fall outside of the offer period in some cases due to a delay in merchants submitting transactions to us or if the purchase date differs from the date you made the transaction (for example, the purchase date for online orders may be the shipping date). If American Express does not receive information that identifies your transaction as qualifying for the offer, you will not receive the additional points. For example, your transaction will not qualify if it is not made directly with the merchant. In addition, in most cases, you may not receive the additional Membership Rewards points if your transaction is made with an electronic wallet or through a third party. ENROLLMENT/ELIGIBLE CARDS: Must add offer to Card and use same Card to redeem. Only U.S.-issued American Express® Cards that are enrolled in the Membership Rewards® program at the time of purchase are eligible. Your enrollment of an eligible American Express Card for this offer extends only to that Card. Your enrollment does not extend to any other Cards that may be linked to the same Membership Rewards program account (such as Additional Cards). Offer is non-transferable. EARNING POINTS: Limit 1 enrolled Card per American Express Card online account. These additional points are in addition to any points you would normally receive for purchases on your Card under the terms of your Card Member Agreement and the Membership Rewards program. When we calculate the additional points benefit for Amex EveryDay® Card products, points awarded under this offer will not be included. Additional points will be credited to your Membership Rewards program account within 90 days after charges appear on your billing statement. Terms and conditions for the Membership Rewards program apply. Visit membershiprewards.com/terms or call 1-800-AXP EARN (297-3276) for more information. Participating partners and available rewards are subject to change without notice. The value of Membership Rewards points varies according to how you choose to use them. To learn more, go to http://www.membershiprewards.com/pointsinfo. By adding an offer to a Card, you agree that American Express may send you communications about the offer. Bonus ID: B2AX; POID: CE1F:0001