Just flew through JFK yesterday 06MAR. First was FLT 60 to BTV with a 0905 departure. We where off the ground with in 10 minutes of pushing. The second was FLT 1010 to BOS (delayed) which departed at 1650. That flight it took us about 20-30 minutes to get off the ground. Both legs we departed off 04L with arrivals on 04R and an occasional departure on 31R.