I was working on the roof of my house on a weekend in the summer/fall of 1999 and to the south I saw three black military looking helicopters flying north, just above the tree tops following the nearby highway 97. Later that same afternoon, still working on my roof I saw one of the black helicopters return, flying low almost directly over my house, seeming to me at the time to be getting a better look at what I was doing on the roof, then after passing over my house the helicopter changed direction and flew off to the north. Later that night at about 3-4 am I awoke to use the washroom. When I returned to my bedroom I saw a moving light out my bedroom window and it caught my attention. I went up to the window which faces almost due north and noticed other lights in a place in the sky I know were not stars. As I watched I noticed 2 stationary lights (I beleive to be helicopters) one at a lower altitude and the other in line at a higher altitude, and a third moving light/helicopter farther to the east. As I watched I realized that a fourth light, between the first two stationary lights and the moving light. doing the same maneuvers as the light that was moving further to the east was doing. I took note of this because the third and fourth lights never went higher(ascend) or lower (decend) than the first two stationary lights. As I watched I noticed that the fourth light was doing the same movements as the third light but at a way faster speed. I noticed that the third light moved as I know a helicopter would move, then when it finished moving the fourth light would do the same movement or pattern as the third light did but it moved unimaginably fast. The third light (which I believe to be a helicopter) would move in many different ways like ascending,descending, form a figure 8 or a Z etc. never going higher or lower then the two stationary lights to the west at different altitudes. And the fourth light would mimic the movements of the moving light but it was moving at a speed and changing directions that no helicopter could ever do. I belive what I was watching was two stationary helicopters at different altitudes and a third, moving helicopter, and some kind of experimental or other worldly aircraft that was being tested. I watched these lights for 15-20 minutes and then returned to my bed to sleep. Being that the event happened so long ago I do not remember the exact month or day but I'm sure it was 1999. I will remember this sighting for the rest of my life.