Variations on the Theme of the Greenberger-Horne-Zeilinger Proof
  Three arguments based on the Greenberger-Horne-Zeilinger (GHZ) proof of the nonexistence of local hidden variables are presented. The first is a description of a simple game which a team that uses the GHZ method will always win. The second uses counterfactuals in an attempt to show that quantum theory is nonlocal in a stronger sense than is implied by the nonexistence of local hidden variables and the third describes peculiar features of time-symmetrized counterfactuals in quantum theory. 
L. Vaidman