Northwest Airlines (NWA) has started a promotion called WorldPerks University. There are four “classes” available in which you briefly review basic information about the WorldPerks program and then answer three multiple-choice questions about the information just presented. Each class takes only a minute or two to complete and rewards you with 100 miles. Also, now that Northwest has merged with Delta, the miles can be transferred to Delta SkyMiles account by linking your accounts – and to make it even sweeter, if you link your accounts before April 30, 2009, you can get another 500 miles in your Delta Skymiles account for a total of 900.

This is a great freebie for anyone who is just under an award level, but also great for creating new reward activity on your account and extending the validity period of your award miles.