Achieve the Core resources and other Math+ Grant Resources
This is the link to the 3rd grade site, but all levels can be accessed from this link.  Note that it will be moving to another link at the end of the year.

Videos

Units for Common core

Instructional Technology Resources

This free site has reading and math common core activities 
This site has nonfiction and fiction reading passages linked to common core Free
Leveled non fiction articles built around current events.  Free
Leveled reading and comprehension questions variety of genres.   Free
Activities for all content areas.  Free version