Best practices for scientific computing. Worth reading if you are, like so many scientists, a self-taught software developer. (Actually, very little of what’s said here is specific to scientific computing.)
Stein’s paradox in statistics, by Bradley Efron and Carl Morris.
The Simons Foundation has an article by Erica Klarreich, Getting Into Shapes: From Hyperbolic Geometry to Cube Complexes and Back”, on Thurston’s geometrization conjecture.
Peter Norvig’s spelling corrector in 25 lines of Python