^If you want to never forget something, picture an absurd
  relationship between the two things. Violence, taboo thoughts,
  blood, ridiculousness - all are things that can help. For
  example, if you are always losing your pen, next time you put it
  down, just as it lands, imagine it being stabbed through the
  surface of the desk with blood spurting out of the desk as it
  screams in pain.

  Trust me: You'll REMEMBER where you left your pen.^