Last update: May,  2009.
Invited plenary talks and courses:

University of Ohio State, More examples of groups, summer school (mini-course)   May 2009
University of Nebraska in Lincoln, Geometric and combinatorial methods in group theory and semigroup theory    May 2009
Centre de Recerca Matemàtica and Universitat Politècnica de Catalunya, Barcelona weekend in group theory   April 2009
University of California, Los Angeles, Quantitative and Computational Aspects of Metric Geometry    January 2009
University of Geneva, Analytic properties of infinite groups    August 2008
Bedlewo mathematical research center, Polish Academy of Sciences, Random groups and graphs (mini-course)    June 2008
University of Neuchatel,  Analysis, geometry and dynamics on groups    June 2008
University of Paris-Sud Orsay,  Geometric group theory in Orsay    December 2007
University of Bourgogne, Algebra and group theory, CLUSE Mathematical School (mini-course)    October 2007
Centre International de Rencontres Mathématiques, Luminy, Words 2007    September 2007
University of Warsaw, the American Mathematical Society international meeting (invited session talk)    July 2007
Bedlewo mathematical research center, Polish Academy of Science, CAT(0) Cubical and Systolic Complexes    June 2007
EPF Lausanne, Random groups (one semester course)    April-May 2007
University of Neuchatel, Groups and Geometry    December 2006
University of Catalunya in Manresa,  the ICM06 satellite conference in Geometric Group Theory with Applications    August 2006
University of Vanderbilt,  Combinatorial and geometric group theory    May 2006
EPF Lausanne, IIIe Cycle Romand de mathématiques (one semester course)    October 2005 - February 2006
University of Neuchatel, Workshop on the Baum-Connes conjecture    September 2005
Centre de Recerca Matemàtica, Barcelona, The geometry of the word problem    July 2005
University of Geneva,  Asymptotic and Probabilistic methods in Geometric group theory    June 2005
EPF Lausanne,  the Swiss Mathematical Society meeting    September 2004
Villars,  Borel seminar summer school (mini-course)    June 2004
Bedlewo mathematical research center, Polish Academy of Science, Geometric group theory    April 2004
University of Athens, Ohio,  the American Mathematical Society meeting (invited session talk)    March 2004
University of NeuchatelInvariants of quasi-isometries    February 2004
University of Aix-Marseille IGroupes and Geometry    February 2002
Yverdon-les-Bain,  the Swiss Mathematical Society meeting (invited session talk)    October 2001
University of Neuchatel, IIIe Cycle romand de Mathématiques, Groupes et Langages     June 2000
Mathematisches Forschungsinstitut Oberwolfach,  Arbeitsgemeinschaft  on Hyperbolic groups    April 1999

Invited colloquium/seminar talks:

University of Vienna   April 2009
University of Fribourg   April 2009
Ecole Normale Supérieure de Lyon    May 2008
University of Lyon I    May 2008
ETH Zurich   April 2007
University of Neuchatel 
   April 2006
ETH Zurich    June 2005
University of Neuchatel    May 2005
University of Lyon I    December 2004
University of Toulouse    December 2004
University of Vanderbilt, Tennessee    March 2004
University Louis Pasteur, Strasbourg    March 2004
University of Neuchatel    December 2003
Centre de Recerca Matemàtica, Barcelona    February 2003
University of Bern    January 2003
University of California in Berkeley    September  2002
University Louis Pasteur, Strasbourg    December 2001
Institute of advanced studies in mathematics, Technion, Haifa    June 2001
Moscow Lomonosov State University    February 2001
University of  Aix-Marseille III    February 2000
ETH Zurich    February 2000
University of Toulouse    Novembre 1999
Institut Fourier, Grenoble    Mai 1999

Invited research visits:

Mathematisches Forschungsinstitut Oberwolfach, visiting researcher    April 2010 / May 2009
/ January 2007 / July 2006 / April 1999
Mathematical Science Research Institut, Berkeley, general member    November 2007
University of Aix-Marseille III, visiting professor    April 2007
University of Hawaii, visiting professor    March 2007
University of Aix-Marseille I, visiting professor    February 2007
EPFL, Bernoulli Center, visiting professor    January-June 2007
Max-Planck-Institut fur Mathematik, Bonn, visiting researcher    June / August 2006
University Louis Pasteur, Strasbourg, visiting researcher    December 2005
Centre de Recerca Matemàtica, Barcelone, visiting professor    October-December 2004
Universitat Politècnica de Catalunya, Barcelone, visiting professor    February 2003
University of Aix-Marseille III, visiting professor    November-December 2002
University of Vanderbilt, Nashville, Tennessee, visiting researcher    September 2002
University of Aix-Marseille I, visiting professor    August 2002
University Louis Pasteur, Strasbourg, visiting researcher    April -- Mai 2000
IHES, Bures-sur-Ivettes,  visiting researcher    January 2000

Other talks / visits / conference participation:

ETH Zurich, Centro Stefano Franscini, Affine isometric actions of discrete groups, co-organizer    June 2009
Bedlewo mathematical research center, Polish Academy of Science, Geometric group theory (session talk)   June 2009
University of Fribourg, Swiss Knots 2009   March 2009
University of Orleans,
Group theory days    December 2008
Centre International de Rencontres Mathematiques, Luminy
, Les groupes de Thompson: nouveaux developpements et interfaces June 2008
Ecole Normale Superieure de Lyon, Glimpses of geometry    May 2008
Diablerets winter school,Groupes et systemes dynamiques    March 2008
Leysin, Around profinite and residually finite groups, co-organizer    August 2007
EPF Lausanne, Bernoulli Center, Geometric linearization of graphs and groups, co-organizer    January 2007
University of Malaga, the ICM06 satellite conference on Groups in Geometry and Topology    September 2006
Diablerets winter school, Mathematical physics    March 2006
EPF Lausanne, Nevanlinna Colloquium    August 2005
ETH Zurich, Symposium Lie groups: from Topology to Arithmetics in memory of Armand Borel    July 2005
University of Neuchatel, workshop on the Relative property T    June 2005
Diablerets winter school, Geometric measure theory, old and new    April 2005
University of Geneva, conference on the occasion of Pierre de la Harpe's 60th birthday    September 2004
ETH Zurich, FIM's 40th Anniversary conference    July 2004
University of Neuchatel, Conference on limit groups    April 2004
Diablerets winter school, Invariants of quasi-isometries, co-organizer    March 2004
Institut Fourier, Grenoble, workshop on Geometric group theory    November 2003
Gaeta, Italy, Combinatorial, geometric and dynamical aspects of infinite groups (session talk)    June 2003
Centre International de Rencontres Mathematiques, Luminy, Geometrie et dynamique des groupes (session talk)    July 2002
Diablerets winter school, Groupe fondamental des varietes hyperboliques    April 2003
University of Neuchatel, workshop on Random walks on Random groups    December 2002
Mathematical Science Research Institut, Berkeley, Commutative Algebra    September 2002
University of Beijing, International Congress of Mathematicians    August 2002
University of Porto, International Conference on Semigroups and Groups    June 2002
ENS-Lyon, Groups and Automata    June 2002
Diablerets winter school, Actions des groupes sur les varetes de petite dimension    March 2002
Centre de recherches mathematiques, University of Montreal, Workshop on groups and 3-manifolds    July 2001
University of Geneva, Matrix computation and statistics    Mai 2001
University of Bern, Seminaire Borel    April-June 2001
Diablerets winter school, Matrices aleatoires et domaines connexes    March 2001
University of Geneva, Colloque CLUSE 2000, Risques majeurs: perception, globalisation et management    September 2000
University of Crete, Groups of tree automorphisms and lattices    July 1999
Diablerets winter school, Metriques Extremales    March 1999
Moscow Lomonosov State University, International Algebraic conference dedicated to the memory of  A.G. Kurosh (session talk)    Mai 1998
University of Bath, Groups St Andrews 1997 in Bath (session talk)    July 1997
University of Saint-Petersbourg, International Algebraic conference dedicated to the memory of D.K. Faddeev (session talk)    June 1997
University of Tula, Modern problems of Number Theory and Applications (session talk)    September 1996
University of Budapest, Second European Congress of Mathematics    July 1996
University of Volgograd, Mathematics. Modeling. Ecology    Mai 1996