Here is a very simple craft we did to go along with our Ice Age theme. I printed out a coloring page of a woolly mammoth (found here) and cut up a bunch of pieces of yarn. After learning about these extinct animals (and using measuring tape to show how long their tusks were -- 16 feet!), the kids used a brush to paint slightly watered-down glue onto the picture.
Fun Fact: The top hairs on a woolly mammoth were three feet long!