Have you visited Thinkfinity yet?
Verizon has partnered with National Geographic Education, AAAS Science Links, Econ Ed Link, Read Write Think, Arts Edge, Smithsonian History Explorer, NCTM Illumination, National Endowment for the Humanities, and Wonderopolis to create a hub of lesson plan ideas, blogs, student interactives, and professional development opportunities. As you can see, the partners in this project are all really top organizations.
One of the greatest parts of the website is that you can search for lesson plans by grade level, subject area, and even specify the partner websites to search, and Thinkfinity does the searching for you. There is a specific link to 21st Century Skills lessons and activities. I also like the "Today in History" calendar.
Also, you can search MN specific standards to see what lessons and activities support particular standards at each grade level.
In the time I've played with the site, I've been impressed with what comes up. You can sign up to receive their newsletter highlighting different aspects of the resource and updates to the site. You can follow Thinkfinity on twitter if you're so inclined.
Check it out!