Not-so-simple stellar populations in nearby, resolved massive star
  clusters
  Around the turn of the last century, star clusters of all kinds were
considered "simple" stellar populations. Over the past decade, this situation
has changed dramatically. At the same time, star clusters are among the
brightest stellar population components and, as such, they are visible out to
much greater distances than individual stars, even the brightest, so that
understanding the intricacies of star cluster composition and their evolution
is imperative for understanding stellar populations and the evolution of
galaxies as a whole. In this review of where the field has moved to in recent
years, we place particular emphasis on the properties and importance of binary
systems, the effects of rapid stellar rotation, and the presence of multiple
populations in Magellanic Cloud star clusters across the full age range. Our
most recent results imply a reverse paradigm shift, back to the old simple
stellar population picture for at least some intermediate-age (~1--3 Gyr-old)
star clusters, opening up exciting avenues for future research efforts.
