This is a two day sale. We say "almost" systemwide because Washington Dulles and Orange County/Santa Ana aren't included.

Travel up until February school vacay, but you can be sure that peak holiday travel will be more expensive on most routes.

Fares range from $49 to $159 each way, which, come to think of it, is pretty close to their normal fares. Book at Southwest.com.

The fine print:

Book by November 13 for travel December 2, 2008 - February 11, 2009.
21-day advance purchase.

Fares do not include federal excise tax of $3.50 per takeoff and landing, airport-assessed passenger facility charges (PFC) of up to $9, and government-imposed September 11th Security Fee of up to $5.00 one-way.

• Available only on southwest.com.
• 21-day advance purchase is required.
• Purchase November 11 through November 13, 2008, midnight central standard time.
• Travel December 2, 2008 through February 11, 2009.
• Fares do not include federal excise tax of $3.50 for each flight segment. A flight segment is defined as a takeoff and a landing.
• Fares do not include airport-assessed passenger facility charges (PFC) of up to $9.00 and government-imposed September 11th Security Fee of up to $5.00 one-way.
• Seats are limited. Fares vary by destination and may not be available on all flights during key travel dates (12/20/08 - 1/4/09).
• Travel not available to/from Orange County, CA or Washington (Dulles), DC
• Offer applies to Southwest Airlines-operated, published, scheduled service.
• This fare is available for one-way travel.
• If combining with other fares, the most restrictive fare's rules apply.
• Tickets are nonrefundable but (except for tickets purchased through our Group Tickets program)
  may be applied toward future travel on Southwest Airlines.
• Fares are subject to change until ticketed.
• Any change in itinerary may result in an increase in fare.