Instructables.com is a website that allows users to post instructions for various projects ranging from costumes to food to electronics. It has a large collection of user-created "instructables" that show how to make or do things. Instructables are organized into helpful categories and most can be created cheaply. While it's easy to get distracted by the many options, Instructables provides a good resource for teachers to find ideas for science projects, arts and crafts, and other classroom activities.