Triangular, 30- 40 seconds, multiple bright lights moving away slowly with no sound at all.I was just arriving out at the expo Building at the Sioux Empire Fairgrounds when I came around the corner and saw a low hover craft which I first thought was a helicopter from the near by Hospital. This craft was making no noise and started to move away from the fairgrounds as soon as I turned the corner around the building to see it. It moved very slowly away heading south easterly. It slowly increased in altitude as it moved away. I watched for several seconds in disbelief and had a very eery sensation come over me. There were several lights on the craft, way more then an aircraft would have and they were so bright that it seemed to mask the actual shape of the object, though I concluded it was a triangular shape based on the points of the lights. The lights were blue, red, and yellow.