It should be noted that in the context of this offer and their trip-bonus system in general, JetBlue does not differentiate between flights. The flight that you take now, at the discounted rate? Oh, that can be some dinky little two-sawbucks-each-way puddle-jumper if you're so inclined - still counts as a promotion-qualifying flight, it does. And the free flight that you take later? Oh, there are no restrictions on that one, either - it's good for anywhere JetBlue flies. So if you can wrangle yourself a seat on a long-haul plane to Bermuda, hey, that's a perfectly valid use of your free round-trip flight right there.
So if you were so inclined, you could buy a flight down to Long Beach... at about a one-third-off discount, on account of the sale price... and parlay that into half a flight to anywhere? Man, that's a hell of a deal right there! And on that note: I am so inclined! So that's what I'm up to this weekend: taking myself a little jaunt down to Southern California, for flight-system-gaming purchases. (Modulo JetBlue staying in business long enough for me to cash in on all my free-flighted goodness, natch. I would probably settle for "not closing up shop while in mid-trip, stranding me in some far-flung city" in a pinch, really.)
Mind you, not that I really have anything to do in SoCal. No family members, no hobby conferences, no super-close friends - nothin'. Which means that this may turn into a Let's See How Many Southwestern Counties I Can Visit affair, for lack of any better idea manifesting. (In the most extreme scenario, where I do not run into bad weather, or some awesome exhibit I want to check out, or get seduced by a truck-stop waitress, or otherwise decide to do anything but maniacal driving, I could probably pull of something like this. The prospect of which is either awesome or terrifying, depending on your vantage.)