LAMMPS workshops have been held in Albuquerque, NM, roughly every 2 years, usually in the summer. The programs, presentation slides, and posters for some workshops can be accessed via the following links. Each workshop included (one or more) tutorial sessions with slides that can also be downloaded.
A July 2018 tutorial and symposium on Modeling Supra-molecular Structures with LAMMPS was held at Temple University.
A workshop-like tutorial and symposium, entitled "Materials modeling with LAMMPS" <!- _http://goo.gl/PpnS6J --> was held in August 2016 at Temple University.
Also see the Tutorials page page for additional info on past LAMMPS tutorials, with lots of downloadable material.