Found this idea over at The Artful Parent. I actually just saw a picture of it and kind-of made the rest up.
All we did was fill a bowl of ice, pour some salt over it (Cooper really loved that part), and Cooper used an eye dropper to cover the ice with colored water. It looked super cool!
When finished we dumped it out in the front yard and then went inside to make some more colored water to make some more colored snow. Too bad I didn't get any pictures of that!