JetBlue is having a fare sale today only for travel through December 15. You'll want to check the fine print and make sure your dates are covered, but it's a great deal if you're willing to travel on non-peak days!
"Offers valid 8/16/11 only (until 11:59 p.m., the earlier of ET or local, or while supplies last) for travel between 9/6-12/15/11. (Blackout Dates: 10/6-10/11/11 and 11/18-11/28/11). Fares not valid for flights on Fridays or Sundays."