Crimson map pack free right now to anyone who was part of the "14 Day, Buy and Play” promotion but had problems downloading the pack recently. The offer is available until December 18.
The pack has to be accessed from the in-game marketplace and not the dashboard or website.
http://www.screwattack.com/news/micr...0%9D-customers
Also read some rumors or speculation that anyone who downloaded the pack when it was accidentally free on the Marketplace will be able to keep it but only until the 18th. After that it gets locked away presumably.