Great post from Miguel Guhlin with many, many examples of icebreakers and many other activities using dice to direct which question or activity someone will use.
Interesting tool bar-can download from CyberSmart, and you are guided to several sites they recommend. In some ways, I like to generate my own, but they undoubtedly have many I'd overlook.
Very thorough list/pages of resources, including organizational tools, student pages, and even book suggestions. Laura Candler sells several things on her website, but she also gives a LOT away for free.
I first marked this page for some excellent links about CCSS for K-6 math, but there are many other great things on the page. While NC's changes would be different from other states, the examples and explanations of CCSS can be useful for anyone.