Sporadic Census
The code for exploring Dirichlet domains for subgroups of PU(2,1) is given below in the form of a Java archive (jar) file:
I am hoping that you run the archive directly (by running "java -jar Sporadic.jar" for instance) and play around to glance at some pretty pictures of faces of domains for the sporadic lattices (see my joint paper with J. R. Parker and J. Paupert).
There is a big chance this will not work (because you are running an old version of java, or because I did not foresee some compatibility problem...) Don't hesitate to let me know if that is the case.
If you like what you see, you may want to tweek the code in order to study other groups (you may just get away by modifying the file "Sporadic.java", depending on what you want to do).