Code
Most things are now on GitHub, which may be more up to date than this list.
Scientific:
clusterdb: quick/dirty searching for known galaxy clusters near some position (Python)
fgas-cosmo: evaluate the cosmological likelihood of cluster gas-mass fractions (C++)
NonGaussianity: evaluate non-Gaussian mass functions (C)
SPA: measure the dynamical state of galaxy clusters (C++)
Statistical:
cstat: utility functions for computing the Cash statistic and its expectation (C, Python)
incredible: utilities for assessing monte carlo Markov chains and computing credible intervals and regions (Python)
LMC: Markov Chain Monte Carlo (MCMC) sampling (Python)
LRGS: multivariate Bayesian linear regression via Gibbs sampling (R, Python)
RGW: the MCMC sampler of Goodman & Weare (2010) (R)
Not code:
cosmo-contours: repository to aid comparisons of cosmological parameter constraints