Registration for Northwest’s “Fly Free Faster 4” promo begins May 15th.

Traditionally the offer is 10,000 bonus miles for one “qualifying activity” (such as a flight, obtaining a Northwest Visa, changing long-distance carriers, or buying miles) and five “partner activities” (such as hotel stays, Northwest mall purchases, dining for miles).

By pairing this promo with a new Worldperks Visa (15,000 mile bonus), signing that card up with iDine, and then going to five different participating bars and ordering a beer at each it should be possible to earn 25,000 miles for about $80.