This happened 15 years ago. I had just finished helping my girlfriend move into her new home, and was heading home myself. I was traveling west on a clear night, when I noticed an object racing across the sky heading east at an incredible speed unlike anything I've ever seen. Then, without slowing down, it made a hairpin turn and headed back west and then just disappeared. What made this so unusual was that it looked just like a star except for it's movement. It first appeared just over the treeline and was almost overhead when it changed direction in just a matter of seconds. I could not even guesstimate it's altitude, although it seemed to be much higher than any manmade aircraft could travel.