Rode out to the Haystack Observatory today. I declare this a mandatory ride if you live in the metro boston area. Very cool huge radar domes and antennae. It was much too hot for this; My friend and I did it as part of an 80mile loop. Ran out of fluids at mild 25, didn't pass another store until around mile 40. Lost 12 pounds (drank 8lbs, scale showed a 4lb different when I got home).
I used this loop out of Lexington:
Its a very nice route with a lot of short hills, one longer hill, and lots of very rural car-free roads!