Beat the heat with a water-themed movie and craft night. First, learn about fresh water ecosystems with the BBC's Planet Earth episode about freshwater lakes and rivers. Then finish off the night by making a small water-based ecosystem of your own to take home. Marimo Moss Balls are small, easy-to-care-for plant pets that are eye-catching and adorable. This is an adult event - participants should be 18 and over. Please register at www.marlboroughpubliclibrary.org Space is limited.