Talk about PERFECT timing! OH I like this one (really like the 1st class one). You can go weekdays and weekends (leave work a little early Friday) and you can do some back to back trips. The CPM is almost good enough to be Skymiles2015 worthy (yeah that low). You can go from either Chicago airport that is closest to you! Here are the numbers:
5,412 MQMs at 4.4 CPM
Bookable on Delta.com
DM yields a nice 12,128 Skymiles per CWSI.net!
As you can see I have included the 1st class run for DEC. Not a lot of dates on that one. Enjoy! – Rene