BIOLOGY/AP BIOLOGY
Howard Hughes Medical Institute
Great resource with videos, animations, lectures, click and learn activities, interactive biology simulations, and much more.
Bozemanscience.com
Review videos for Biology and AP Biology
Khan Acadamy
Gives overview of main topics in biology. Has sample quiz questions and sample Unit Tests
Learn Genetics
Biology resources with review material, student activities, simulations, current events, and much more.
CHEMISTRY
chemfiesta.org
PHYSICS
Khan Acadamy: AP Physics 1
Just videos right now although they promise practice problems at some point.
AP Physics 1 Released Free Response Questions
AP Physics C Released Free Response Questions