Start every day with an invigorating (mental) workout! Our 2018 365 Brain Puzzlers Page-a-Day Calendar is a compact "gym" loaded with a year's worth of Mensa-approved logic puzzles, math problems, spatial challenges, encoded words, and more brain-busters. And after you do your heavy-lifting, peek at the back of each page for the answer or explanation for each challenge. It's a terrific gift for the know-it-all you know and love.