a bright light in the night sky started to move in a zig zag counter clockwise pattern, hovering in one spot occasionaly.I was spending my night off of work at the park because that is the best place to see the stars clearly (i like to behold existence). anyways, i was looking up at the stars and what i thought was a particularly bright star started to zigzag in a counter- clockwise motion. it moved on and off again in the same pattern for the duration of about 15-20 minutes, finally coming to rest in it's original position.I'm not trying to put my contact info!! I live about 10 miles south east of lake tahoe so, from my perspective, the incident appeared in the night sky over the Heavenly Ski Resort, above the mountain outline. It was changing colors from whitish to red and blue very rapidly, and during the incident it appeared that part of it detached and flew off unbelievibly fast, but it was hard to be certain.