An excellent edition of Math Teachers at Play is up at mathrecreation.
The Carnival of Mathematics has now had a proper revival thanks to Mike Croucher; I will be hosting the next carnival here on November 6, 2009. You can use this submission form to send in your entries.
Everything math-related goes in here: proofs, explanations of basic concepts, puzzles, writings about math education, mathematical anecdotes, refutations of bad math, applications of math, reviews of popular math… Note that sufficiently mathematized portions of other disciplines, especially physics and computer science, are acceptable.
While Math Teachers at Play is dedicated to just K-12 appropriate mathematics, the Carnival of Mathematics is additionally open to research math of any level of depth.
Here are the prior carnivals I hosted:
Filed under: Mathematics