Mostly sunny afternoon. I was hanging upside down on playground equipment at a parochial school. I saw twinkling objects in the Northwest sky. I thought i had been upside down too long. but when i regained my balance they were still there. I contacted my school principal. He told me he would call the proper authorities. Everyone on the playground seen it. there were a multitude of twinkling lights way up in the sky. all silver. very small but yet visibly shining. there was also an airplane coming in from the southwest, it went behind a cloud and there was a loud explosion. I never saw the plane come back out of the cloud. nor did i see anything fall out of the sky. My principal got back to me and told me the airforce had checked out the lights. I was told it was just tinfoil in the sky. I never saw any report on this incident.