The spatially-indirect exciton condensate (SIXC) is an interesting ordered electronic state in
which coherence is spontaneously established between particles localized in separate two-dimensional layers. To date SIXC states have been discovered only in dou-ble-quantum-well semiconductor heterojunctions and only in the strong magnetic field quan-tum Hall regime. I will discuss some properties SIXCs, commenting on their counterflow superfluidity, their collective excitations, and on similarities and differences relative to su-perconductors, easy-plane ferromagnets and anti-ferromagnets, and the standard model of particle physics. Finally I will discuss the some recent theoretical work SIXC states in bi-layers formed from two-dimensional materials, which will hopefully be observed in the fu-ture.