JetBlue has launched a sale today sure to fill up those birds with passengers. Just $10 gets you a one-way, nonstop flight anywhere (including international destinations) in the JetBlue network. Valid for travel May 11-12th only. You can combine two one-ways for a $20 roundtrip flight + taxes and fees. I also noticed some 1-stop flights, such as Sacramento-Long-Beach-Las Vegas for $20+ each way.
Don't forget JetBlue is one of the few remaining airlines that also lets you check one piece of luggage for free, and does not overbook their flights. Plus they have comfy leather seats, Direct-TV and tasty munchies on board.