Not a near miss, but a bizarre takeoff. I was flying from Phnom Penh to Saigon three years ago in a brand new Air Vietnam ATR72 (with French registration numbers). Started down the runway, and at what I figured was close to liftoff speed, the pilot powered down the engines. For a minute or so the plane sat in the middle of the runway, then the pilot gunned the engines and proceeded to continue the same direction and take off. However at this point, he only had somewhere around half the runway length to use.

Take off and rest of the flight was uneventful. I recognize the ATR is a short take-off plane, but this was an eye-opening stunt.