In this talk, I will give an overview of work I've done in the last year on computing various transcendental functions in interval arithmetic. The first notable result is a large (order of magnitude) speed improvement for elementary functions. The second project concerns generalized hypergeometric functions (including the incomplete gamma function, Bessel functions, and others). This is still a work in progress, and some significant problems remain, particularly the task of computing useful enclosures when the inputs are large, inexact complex numbers. Finally, I have a fairly complete implementation of the classical Jacobi theta functions, elliptic functions and modular forms. I will describe an optimization for theta series, following up the results presented earlier by Andreas Enge (2015-06-02), and discuss the application of computing class polynomials.