I realize that some of these math puzzles are geared for the elementary level, but some of these puzzles could be used in high school level as a fun activity.
http://www.edhelper.com/puzzles.htm?gclid=CImEqO_j4ZYCFQMQswodFjaoPg
On this website, you can choose your math subject area and it will provide you with those games for that content area. http://www.awesomelibrary.org/Classroom/Mathematics/Middle-High_School_Math/Middle-High_School_Math.html
http://www.cut-the-knot.org/games.shtml
http://www.funbrain.com/teachers/grade_hs.html
--Akcooper 19:27, 6 November 2008 (UTC)