My 2 daughters, a friend, and I were standing outside (beautiful, clear night) at about 11pm on 4/20/14 when I saw a bright purple light in sky slowly heading from east-west. It stopped almost directly above us and I pointed it out (I said that I'd never seen an airplane or satellite with purple lights) so we all were watching when it stopped in place for about 10 seconds, then immediately went back in opposite direction at much higher rate of speed. We thought it was a plane crashing, but it stopped near the horizon and shot straight up in the air for an (estimated) 500 feet, stopped, and dropped back down again. It did this 4 times, then it went back toward horizon and disappeared. It was definitely the strangest thing I've ever seen, especially the abruptness and maneuverability at such a high speed. It covered a lot of ground very quickly and changed direction without any visible arc or turn like an airplane would have to make.