The first paper I read for Causal Dynamical Triangulations is a fairly steep introduction (for me), so I went and looked over the 2D case and lessons, as well as a general review of methods.
I'm also looking at SAGE, Software for Algebra and Geometry Experimentation, a free mathematical programming system using Python + a lot of open source tools. On Windows, SAGE requires VMWare and uses firefox. You can use it online, but so far it's rather slow, and appears to have been slashdotted.
Impressive tool! Feels a lot like Mathematica, accessible via web browser. The tutorial is well-worth running through (I used the on-line version while upgrading my local install, but the local version allows you to run the calculation cells using Shift-Enter ).
For example, SAGE extends Python to handle rings and p-adic numbers (which I learned, should always have a prime number base to avoid the zero-divisor problem).
Adding dvipng SAGE package requires adding ghostscript, via apt-get install gs.
Also requires libkpathsea, which requires tetex via apt-get install tetex-extra
PostScript: the SAGE dvipng package doesn't work, but apt-get install dvipng puts dvipng on the system, which should suffice.
Note: SAGE runs on Edgy, and can be updated to Feisty by using update-manager-core as described here. The SAGE-support group is available on Google Groups.
PostScript: SAGE can be upgraded to Gutsy, I used the Upgrade Manager available in Xubuntu (I wanted a GUI for some SAGE file management via apt-get install xubuntu-desktop)
Doesn't work yet on BSD, alas, and running a SAGE server has security implications.