Math Aligned with the Standards

http://www.k-5mathteachingresources.com/

This site is phenomenal! It is a teacher's dream come true! This site not only provides teachers with grade by grade hands-on activities, but it goes one step further by aligning the activities with the Common Core State Standards for Mathematics!!! This site can be broken down by grade or by major concept (number, geometry, etc.), provides e-books, tips on classroom organization, resources for mental math activities as well as place value strategies, and many other resources.
This site is easily a go-to site for my classroom. I can go to this site knowing which standard I am teaching to and have a specific activity already aligned directly with it, plus additional resources at my fingertips. This site would also be a quick place to go and find activities for a substitute where the directions are already provided and can be put into a lesson plan that they can teach to students without going off on a tangent from what students were learning.