The longest take-off roll I ever saw was that of the Voyager, flown by Dick Rutan. Dick took the stage while I was in the Smithsonian's I-Max theater, sitting next to the late Steve Fossett. As Dick reached the lectern, the take-off roll for this first non-stop flight around-the-world without refueling was shown. Steve and I were discussing Steve's then planned first non stop flight around-the-world in a jet without refueling while Dick's take-off roll was still progressing. We talked for what seemed like a good while - actually a bit short of three minutes, looked up at the screen, saw the Voyager was still rolling, looked at each other and just laughed. Below is the link to what we saw that evening in 2004.
Save the Earth; it is the only planet with chocolate.