The mechanical properties of graphene-like systems are proving to be quite unique; for instance, carbon nanotubes demonstrate elongations exceeding 200% at under tensile loading at high temperature.  I will describe some of our recent computational efforts at understanding the role of defects in the plastic deformation of carbon nanotubes and graphene sheets.  We have developed a topological, continuum theory of defect energetics in carbon nanotubes and graphene, which accurately reproduces ab initio results for a variety of defect geometries.  I will describe our theory in detail and show how we can use it explore deformation mechanisms via both Kinetic Monte Carlo and dislocation dynamics.  Time-permitting, I will also discuss more recent work in modeling the growth of carbon nanotubes by catalyst-assisted chemical vapor deposition, emphasizing again the role of defect topology in nanotube synthesis.