``Coxeter groups and Artin groups,'' a series of four talks, Workshop on combinatorial, algorithmic and cryptographic aspects of group theory, Luminy, CIRM, Marseille, France, February 2007
``The geometry of groups defined geometrically,'' a series of four talks, Workshop on Geometric Methods in Group Theory, Fields Institute, Ottawa, Canada, August 2006
``Constructing nonpositively curved spaces and groups,'' a series of four talks, Durham Symposium on geometry and cohomology in group theory, Durham, England, July 2003