My children absolutely loved this activity. Although it needed a little pre-planning (which they were part of), this activity kept them busy for nearly an hour.
Collect (or get your children to) lots of small plastic toys. Put them into a large bowl and fill with water (leave about an inch at the top for the water to expand)! Put the bowl in the freezer.
The next day get a washing up bowl and upturn large frozen bowl into it. Give the children spoons and a squeezy bottle of warm water and let them get excavating!!
It took about an hour, and lots of warm water, to free all the plastic toys from the ice. What fun!! Thanks for reading!