Other web content can be found at the University of Washington.
A few key software packages are listed here.
This is a massively parallel astrophysical N-body/SPH package. Documentation can be found on the wiki
This is a parallel visualization package for ChaNGa output. Documentation can be found on the wiki
This is a classic visualization tool for N-body simulations. Documentation can be found by reading the code.
There are a cast of thousands.
Use the issue trackers on the appropriate github repository to report problems.