Conference Homotopical methods in algebraic geometry, University of Southern California June 2013 Colloquium, University of California, Berkeley May 2013 Conference Interactions between Noncommutative Algebra, Representation Theory, and Algebraic Geometry, MSRI, Berkeley April 2013   Conference Motives, Tokyo, Japan December 2012 Conference Algebraic Topology, Arolla, Switzerland August 2012 Conference Periods and Motives, Madrid, Spain July 2012 Lunch seminar for graduate students, Massachusetts Institute of Technology May 2012 Conference Noncommutative Algebraic Geometry and its Applications to Physics, Leiden, Netherlands March 2012 Colloquium, California Institute of Technology January 2012 Algebraic topology seminar, Massachusetts Institute of Technology November 2011 Seminar on Algebra, Geometry and Physics, Max-Planck-Institut fur Mathematik, Germany July 2011 Conference Triangulated categories and applications, Banff Institute, Canada June 2011 Representation theory seminar, Northeastern University April 2011 Midwest Topology conference, University of Chicago April 2011 Geometric Langlands seminar, University of Chicago April 2011 Noncommutative geometry seminar, California Institute of Technology March 2011   Noncommutative algebraic geometry seminar, Massachusetts Institute of Technology January 2011  Conference Homotopy theory and derived algebraic geometry, Fields Institute, Toronto, Canada August 2010   Conference Topics in Noncommutative Geometry, Buenos Aires, Argentine July 2010 Algebraic topology seminar, Northwestern University May 2010 Algebraic topology seminar, University of Illinois at Urbana-Champaign April 2010 Algebraic topology seminar, University of Chicago April 2010 Algebraic topology seminar, Massachusetts Institute of Technology March 2010 Algebraic topology seminar, Stanford University May 2009 Algebra seminar, University of California at Los Angeles May 2009 Conference Cats 3, Centro di Ricerca Matematica Ennio De Giorgi, Pisa, Italy September 2008 Algebraic topology seminar,  University of Bonn, Germany July 2008  Conference Homotopy Structures in Geometry and Algebra, Centre de Recerca Matematica, Barcelona, Spain June 2008 Algebra seminar, Laboratoire J. A. Dieudonne, Nice, France April 2008