For a holiday party: Fill balloons with water colored with food coloring. Set them out when it's below freezing. After they've frozen solid, remove the balloons and you'll have something resembling giant marbles.
Frozen Frogs In Alaska - During the cold winters, the Alaskan Wood Frog becomes a frog-shaped block of ice. It stops breathing, and its heart stops beating. When Spring arrives the frog thaws and returns to normal going along its merry way.