I filled a 9x13 glass casserole dish with snow. It's great snowman snow and made snowballs very easily, which M loved. I also got three small containers, filled the each with cold water and added a drop of food coloring to each. I gave M a big mixing spoon and a cooking brush to "paint" with.
At first M was pretty surprised that the snow could change color. Pretty soon he was painting and eventually dumping the water into the snow.
We used yellow, red, and blue water which worked well because it mixed into green, purple, and orange so at point we had a pretty good rainbow of colors going on...until it turned to a peach colored slush.
We made snowballs, a snowman, and built some towers that M enjoyed knocking over with the spoon. Eventually about half the snow had melted leaving a coating of water on the dish. The snowballs that were left could easily slide and spin on the wet surface, which M really enjoyed too. All in all it served it's purpose- pushing our journey outside back a few hours.