The 47th Carnival of Mathematics has been put together by jd2718; go give it a read! Some of my favorite posts include factoring by puzzles, teaching binary numbers, the 2009 game, cliques of dichotomies, but there is lots of other interesting stuff as well.

Kalid Azad of BetterExplained has a great article about developing your intuition for mathematics that I also wanted to share.

Finally, here is xkcd‘s useful guide to converting to metric.

Hi Brent, thanks for the mention! I enjoyed writing that article, glad you found it useful :).