In a night sky 5 silver/blue lights circled in a circle, joined at the center, repeated the event & then the joined lights went out.I opened my back door to put a dog out and immediately noticed that five silver/blue gray lights were circling above in the sky. I don't know how long it had been occurring but I watched them for about thee minutes before the event stopped. The lights seemed to circle independently, each moving in the circle while moving but not in a locked position; each seemed an independent light darting about with the others and together forming a rough circle for a time and then at the same time joining together at the center. They did not form a perfectly round center light when they joined; that is each round light seemed to remain separate and "touch" the others at the center, forming a larger irregular center light . Then they went back out again to form the circle and repeated this process over and over. At the end they joined in the center and, after maybe 10-15 seconds, the lights just "went out." At the end the lights seemed to be more like one light, more totally merged into one. I live near an airport but the lights were not like any I have ever seen and did not behave like the lights that the airport uses. I have only once before experienced anything that I could remotely call a UFO sighting, four and a half years ago from this same house, but that time it was more like a bright star type light, two of them darting and then coming together before the light went out when they last joined. This time the lights were very soft and diffuse looking, there were more of them, and they behaved very differently. I'm thrilled to have seen it and wish my neighbor was not away on a camping trip!((NUFORC Note: We observe that the report is not inconsistent with a "sighting" of an advertising light, swirling in the night sky. Just a guess. PD))