``Instability in Triangle-Square Complexes,'' Topics in geometric group theory conference: CAT(0) cubical and systolic complexes, Mathematical Research and Conference Center, Bedlewo, Poland, June 2007
``The Intrinsic Geometry of Groups,'' Modern Mathematics: An Introduction to 2007-08 Programs at MSRI, SACNAS conference, Tampa, Florida, October 2006
``Pulling apart orthogonal groups to find continuous braids,'' Conference on Geometric Group Theory, Centre de recherches mathématiques, Montreal, Canada, July 2006
``Coxeter groups and Artin groups in geometric group theory,'' Flavors of Groups, Banff Workshop, Banff, Canada, November 2005
``Artin groups and polytopes'' Wasatch topology conference, Park City, Utah, June 2005
``The integral cohomology of the group of loops and a conjecture of Brownstein and Lee,'' Sixth UCB-UCSB Algebra Day, June 2005
``Noncrossing partitions for arbitrary Coxeter groups,'' Institute for Advanced Studies / Park City Mathematics Institute on Geometric Combinatorics, Park City, Utah, July 2004
``Expansions of semigroups,'' International meeting on Semigroup Theory and Related Topics, Braga, Portugal, June 2003
``Finding parking when not commuting,'' Workshop in Geometric Topology, Park City, Utah, June 2003
``The role of curvature in combinatorics,'' Conference on topological and geometric combinatorics, Mathematisches Forschungsinstitut Oberwohlfach, Oberwohlfach, Germany, April 2003
``A geometric approach to semigroup theory,'' International Conference on Semigroups and Groups, Porto, Portugal, June 2002
``A geometric approach to semigroup theory,'' AMS-UMI Joint meeting in Pisa, Italy, June 2002
``A new class of nonpositively-curved 3-manifolds,'' Spring topology conference, Austin, Texas, March 2002
``Algorithmic aspects of nonpositive curvature,'' CRM Groups and Low-dimensional topology conference, Montreal, Canada, July 2001
``Calculating the curvature of concrete complexes,'' SUNY-Albany Topology and Group Theory conference, Albany, New York, Oct 2000
``The curvature of posets associated to the braid groups,'' International Conference on Geometric and Combinatorial Methods in Groups and Semigroups, Lincoln, Nebraska, May 2000
``Curvature and quasiconvexity in geometric group theory, I: curvature,'' Wasatch Topology Conference, Park City, Utah, August 1999
``Curvature and quasiconvexity in geometric group theory, II: quasiconvexity,'' Wasatch Topology Conference, Park City, Utah, August 1999
o``Extending Stallings' algorithm to 
-complexes,''
AMS-IMS-SIAM Joint Summer Research Conference on Geometric Group
Theory and Computer Science, Mt. Holyoke College, July 1998
``General versions of small cancellation theory,'' Topology Festival, Cornell University, May 1998
``The solution of the word problem for the Burnside semigroups,'' Marquette Symposium on Semigroup Theory and Its Applications, Marquette University, March 1991