Spitballs.
They are these gelatinous balls that grow in water. Our 6-year-old's teacher along with the school's principle gave one to each student during a class science experiment

confused3). She dropped her's at home, and it broke. She was devastated. Luckily, like seriously luckily, Santa was able to get the kind folks at ThinkGeek to send her her own package of a whole bunch of spitballs. She will be thrilled.
For kicks and giggles, here they are:
http://www.thinkgeek.com/geektoys/science/cd32/