A feasible "Kochen-Specker" experiment with single particles
  We present a simple experimental scheme which can be used to demonstrate an all-or-nothing type contradiction between non-contextual hidden variables and quantum mechanics. The scheme, which is inspired by recent ideas by Cabello and Garcia-Alcaine, shows that even for a single particle, path and spin information cannot be predetermined in a non-contextual way. 
Christoph Simon, Marek Zukowski, Harald Weinfurter, Anton Zeilinger