  One of the defining processes which govern massive star evolution is their
continuous mass loss via dense, supersonic line-driven winds. In the case of
those OB stars which also host a surface magnetic field, the interaction
between that field and the ionized outflow leads to complex circumstellar
structures known as magnetospheres. In this contribution, we review recent
developments in the field of massive star magnetospheres, including current
efforts to characterize the largest magnetosphere surrounding an O star: that
of NGC 1624-2. We also discuss the potential of the `analytic dynamical
magnetosphere' (ADM) model to interpret multi-wavelength observations. Finally,
we examine the possible effects of -- heretofore undetected -- small-scale
magnetic fields on massive star winds and compare their hypothetical
consequences to existing, unexplained observations.
