My kids had a blast with this!
Take normal blowing bubbles (I used the small wedding bubbles, they were easier to deal with) and add a few drops of food coloring to them. Close the lid and shake it up a little.

Provide white paper for the kids, and have them blow bubbles onto the paper. Makes some pretty neat designs, they have fun blowing bubbles, and with my kids since they are only 2, it allows them to get that blowing technique down.