Rachel Lynette, over at the “Minds in Bloom” blog, offers some fun Halloween activities for critical thinking. One of them is a Halloween-themed list of “Would You Rather?” questions. For these, I would recommend that you encourage your students to justify their answers, and possibly have a contest for who can give the most unusual reason for his or her response. (For another way to use “Would You Rather?” questions, check out this post.)
Rachel also has a free “GHOST” Scattergories-type game that you can print. As an extension, you could have the students make their own spooky versions by changing the letters on top and the categories.
And, finally, incorporate some disgusting math into your Halloween plans by giving your students some “Witches’ Brew Math.” Boiled eyeballs, anyone?