For 14 days Alaska Airlines is discounting one city each day by 30%. This is really a great promotion that I will be viewing on a daily basis. Today's special (4/17) is Calgary and lasts until 11:59pm Pacific time. The daily discount is unveiled at midnight each night during the promotion.
Destinations which have been previously discounted are:
April 14th - Phoenix
April 15th - Newark
April 16th - Ixtapa, Mexico
It's impossible to know which cities will be part of the promotion, but cities of note which haven't been used yet include: Seattle, Boston, Washington DC, Miami, Orlando, Cancun, Mazatlan, Los Cabos, Puerto Vallarta, Austin, Dallas, Chicago, Phoenix, the Hawaiian Islands, and most all of the Southern California.
I will be sending out updates on this promotion daily via twitter if you care to follow: http://twitter.com/TravelGuyTravel