KLM had an interesting social media promotion on their Facebook page where fans could vote on where they wanted a seat sale to happen. The winner was Lisbon (I actually went to the castle pictured below on my trip to Lisbon this past January).
One of the benefits of KLM is the free stopover (can stopover in Amsterdam at no extra cost or Paris).
Travel season is from Oct. 16 to Dec 14, 2013 or from Dec. 25, 2013 to May 6, 2014. Weekend surcharge apply