American Express Promo: 5 Cents Back on Mobil/Exxon Purchases
While not necessarily a "points" promotion, I thought this was a pretty good, money saving promo. Registration link.
Sign up and save when you use any registered American Express® Card at any Exxon or Mobil station.
Earn 5-cents back on every dollar you spend when you use your registered American Express Card to fill up at any Exxon or Mobil station between December 20, 2010 and January 20, 2011.