JetBlue must want to get some cash on the books, because they're offering 20% off fall airfare when you travel Sep. 7 through Oct. 29. Use coupon code FALL2011. Here's the fine print:
"Discount Codes are case-sensitive; redeem at jetblue.com/promo; valid for 20% off roundtrip base fare for travel from Any JetBlue city to Any JetBlue city 9/7 – 10/29/2011. Blackout dates: 10/7 – 10/10/11. Travel must originate in the U.S. Discount deducted off base fare."
That's so far in advance that I'd be a little hesitant to buy - who knows what airfare prices will do in the meantime, and they say the best time to buy your tickets is 4-6 weeks before you travel. But if you know you're going somewhere on those dates and you want to get the airfare taken care of, this might be a good deal for you.