This site is very well organized, and has lots of examples in many subjects. Uh-ho - you gotta sign up. It's worth it though. The lessons are obviously done by experts.
This site helps enhance and develop learning skills in many content areas. BrainpopJr is for K-8 and the regular site (www.brainpop.com) is for students in grades 4-8. I enjoy this site because it allows students to go to specific subjects and learn about them in a fun and interactive way.