Motivated by the need to construct models of slender elastic media that are versatile enough to accommodated non-linear phenomena under dynamical evolution, an overview is presented of recent practical applications of simple Cosserat theory. This theory offers a methodology for modeling non-linear continua that is physically accurate and amenable to controlled numerical approximation. By contrast to linear models, where non-linearities are sacrificed to produce a tractable theory, large deformations are within the range of validity of simple Cosserat models. The geometry of slender and shell-like bodies is exploited to produce a theory that contains as few degrees of freedom as is physically reasonable. In certain regimes it is possible to include fluid-structure interactions in Cosserat rod theory in order to model, for example, drill-string dynamics, undersea riser dynamics and cable-stayed bridges in light wind-rain conditions. The formalism also lends itself to computationally efficient, effective models of microscopic carbon nanotubes and macroscopic gravitational antennae.