Each year Northwest has a special promotion where you can earn bonus WorldPerks miles for flying, renting a car, shopping online, and signing up for various offers. These promotions are usually in addition to miles you would already earn for participating in these activities.
Northwest has rolled out another such program, this time called "Miles To Go." Here is a comprehensive list of activities and corresponding point value for completing them. To the right is a conversion chart of points to miles. The more activities you complete, the more points you earn. The more points you earn, the more Northwest WorldPerks miles you bank.
Of course flying Northwest will earn you the most bonus points/miles, but there are plenty of other easy-to-do ideas listed. For example, unlike past promotions you can simply enter the daily instant win game to earn 5 points a day (every day!), or enroll in the Northwest WorldPerks program for 25 points.
Miles to Go runs through July 31st. Be sure to read all the rules, then register before completing any of the activities.