Introduction to Quadratic Forms and Modular Forms
MSRI -- August 2006 (video)

The 290-Theorem and finiteness theorems for quadratic forms
University of Waterloo -- Seminar -- November 2006
University of Georgia, Athens -- Seminar -- November 2006
University of Arkansas, Fayetteville -- AMS Special Session -- November 2006
University of British Columbia -- Seminar -- October 2006
University of Washington -- Seminar -- October 2006
UC San Diego -- SAGE Days Conference -- February 2006
Boston University -- Seminar -- November 2005
Finiteness Theorems and representing numbers by a quadratic form
University of Chicago -- Seminar -- June 2005
University of Michigan -- Seminar -- April 2005
Harvard University -- Basic Notions Seminar -- February 2005
Duke University -- Algebraic Geometry Seminar -- September 2004
The Cuspidal structure of certain ternary theta functions
Western Kentucky University -- AMS Special Session on L-functions -- March 2005
On a Local-Global principle for ternary quadratic forms
Wesleyan University -- Algebra Seminar -- April 2003
Harvard University -- Modular Curves Seminar -- March 2003
Duke University -- Algebraic Geometry Seminar -- November 2002
Park City Math Institute -- July 2002
University of Montreal -- Canadian Number Theory Association Meeting VII -- May 2002
What numbers can be represented by a quadratic form?
Princeton -- Number Theory Seminar -- February 2001
An exact mass formula for orthogonal groups
Penn State University -- Seminar -- February 1999
Princeton -- Algebra Seminar -- December 1998

Guest Lecture on the Analytic theory of quadratic forms
Princeton University -- Fall 2005
Harvard University -- Fall 2003