That sprinklers hitting balloons make a very odd and very loud sound?
Last night I heard the oddest noise. It was very loud and I could not figure it out. It was a strange whooshing/drumming noise that would last about 5 seconds, pause for two minutes than another loud 5 second pulse of noise followed by a 10 minute pause. It kept repeating and driving me batty. I finally got up and staggered about trying to locate the noise. I finally stuck my head outside when I noticed the sprinklers were going.
Then I saw what was happening. The sprinkler was hitting a balloon tied to a bench outside. Mystery solved I was able to go to sleep. This morning I got rid of the offending balloon.