Inspired by Daniel Norton photographer, I thought I'd give this a go! Not ideal conditions as I was shooting outdoors due to lots of water spillage. I also broke a couple of glasses too! Let me know what you think, or even try it yourself ; )
Setup: Both speed lights on their lowest setting (to freeze the action) Camera on fastest flash synch speed and aperture to suit (I used F4). Throw the ice cube into the glass at same time as pressing the shutter button. Manual focus may be the best setting so you freeze the water. Luck!