Especially if it's very, very cold and you get a little chemistry involved!
You'll only need cold weather, food coloring or liquid watering color paints, bowls and bowls (of all kinds of shapes and sizes, water, and a bit of curiosity about how colors are made. And salt, if you like.
When you're all done playin' -- or have run out of bowls, carefully take them outside to freeze.We set ours out over night.
When we were ready to play, we set a large towel on the table to catch the drips.
The ice will come out of the containers easily with a bit of hot water run over it if they're stuck.
If you'd like to make it interesting - which we always do - then grab the salt shaker.
If you're playing outside or if your ice is not watery and melted on the outside, you can stick two pieces of ice together by adding a touch of salt - but it won't work if the outside of the ice isn't dry.
(The salt causes the surface of the ice to melt until diluted, then when you place ice on top of it, it causes the water to freeze again.)