The RO(G)-graded coefficients of (Z/2)^n-equivariant K-theory
  In this note, we calculate all untwisted and twisted (Z/2)^n-equivariant K-groups with compact supports of real finite-dimensional linear representations of (Z/2)^n. The question was motivated by the question of D-brane charges for orbifold type II string vacua. 
Po Hu, Igor Kriz