I do research on elliptic curves and modular forms and direct the Sage software project (http://sagemath.org)
I am a professor of mathematics at University of Washington (http://wstein.org). In my mathematics research, I use the Birch and Swinnerton-Dyer conjecture as motivation to understand the constellation of arithmetic invariants associated to optimal quotients of J0(N). I also use do explicit computations with modular forms.
I also love skateboarding: mostly big vert halfpipes, then concrete bowls, then miniramps, then street.