BrainPOP
BrainPOP Educators allows you to search by subject taught and grade level (my personal favorite feature). It provides links under each under TEKS.
Mixer allows you to create your own quizzes from scratch or add questions from other teacher created quizzes.Make a (concept) Map allows the student to create a concept map about the video watched.
Game Up allows you to to have students play games that reinforce skills taught in class.