Raindrops [via mental_floss Blog] - Fun, simple flash-based addition/subtraction game. Equations fall from the sky, and you have to solve them before they fill up the lake below. Seems most appropriate for grades K-3
The Man Who Could Unsnarl Manhattan Traffic [Wired, June 2010] - Great example of a practical, real world application of data analysis and statistics. Could be an interesting jumpstart for a discussion in an upper level math class.
"Nudging" Students to Eat Fruit Could Be Key to Better Lunches [GOOD] - New research shows that by simply changing the logistics of the cafeteria, such as how good foods are presented and the way students pay for lunch, is more effective and beneficial than more expensive changes. This sounds strangely like what teachers must often do in the classroom: "selling" our students on the importance of unappealing and uninteresting topics by presenting it in an engaging way.
Dead Class Pets - If you like the blog Look at my happy rainbow!, a personal favorite I link to constantly, you'll appreciate the classroom stories of Washington, D.C. elementary teacher Sarah Garb.
End of Year Reflection [Misscalcul8] - If you're trying to make sense of the school year that just ended, here's a thoughtful and thorough model to follow when you do so.