Speaking of applying flap halfway through the takeoff run... My instructor thought he'd teach me something new on Sunday afternoon. Took off from a rather soggy grass field strip in a PA38, started the takeoff run clean, got to about 52kts and my instructor put down one stage of flaps. Left the ground like a flippin' rocket.
Had my first taste of short field landings as well - 65kts over the threshold, flare, screach to a halt using about 1/5th of the runway. Now I know what carrier landings must feel like...