This is a list of 100 social studies apps/websites/resources for kids. If one of them pertains to a specific unit/lesson you can have the students play/explore the content. You could also have them play these social studies games in their free time.
Great apps for ELLs and students with special needs
This is 10 Free Learning Websites for Kids to use. A child specialist could have computers linked to these free fun websites. It could be for children who want to do something educational and with electronics.