Our local radio station has a "secret sound" competition and for the last six months, nobody's been able to guess what the sound is. Here's the sound:
https://cml.sad.ukrd.com/audio/446814.mp3

Any of you know what it is? You could win nearly £2,000. Here are a list of incorrect guesses:
http://www.klfm967.co.uk/win/the-secret-sound/