The homework help section provides excellent resources. You can choose a subject, skills or types of reference resources.
Fact Monster is engaging for students from elementary through middle school. I have worked with teachers who use it for lesson review, afterschool program activities and homework. Fact Monster has interactive quizzes that provide instant feedback.
I have added a screen shot of the tool bar that keeps it simple with good visuals for easy searching.
Check out Fact Monster and all the various components you can use to enhance a lesson. Share a comment about how you use it or what your students think about the site. Sharing builds community!