Highlights include code for
- Commutative algebra, including Gröbner basis computation and tools for manipulating ideals of rings.
- Permutation groups, including an implementation of the Schreier-Sims algorithm and tools for investigating the Rubik's cube group and its subgroups.
- Number theory. Includes tools for working with quadratic fields, p-adic numbers and elliptic curves, and code for factoring using Lenstra's elliptic curve algorithm.
The full repository is here. (Use that link to download the code as some of the other links appear to be broken right now.)
It'd be great to see a textbook grow out of some of this work...