It's probably not what you'd expect+ READ ARTICLE
Cory Williams, who runs a YouTube channel all about life in Alaska, made a very interesting discovery lately: skipping rocks on a mostly frozen lake leads to a surprisingly cool sonic experience (skip to 3:45 in the video to hear). Williams was totally not expecting the sound, which is kind of like a laser or some kind of chirping bird. Watch as he gets really, really excited about this revelation and then searches for more stones so he can hear the sound again.
Though this experience was new to Williams, several other people have tried it and had similar results: