Requested by @sarah
  1. Brain Teasers
    I recommend the Khan Academy brain teasers. Warning: could consume your life for the next few days.
  2. Rubik's Cube
  3. Logic Grid Puzzles
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    This type of puzzle uses deductive reasoning, following the lines of 'if A is B, then C can't be D'.
  4. Tatami
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    Hidden Gem: Tatami is like a cross between a Logic Grid puzzle and Sudoku. For intense Logic and number lovers.