KDP - free to use but no source code a derivative of ACOS?
Opus (A C++ open source (gnu) software - code provided!!!!)
Non sequential software (yes the above codes do non sequential as well)
GOptical (Another gnu ray trace software in Python?)

Optics Resources:
SPIE Optipedia - a wiki for optics!
The Science of Light. Powered by Optical Society of America (OSA) to educate kids about optics
Online database of starting optical designs.
Amateur Telescope Making (ATM) by Stellafane
Atmospheric Optics. "What makes a rainbow dad?" Cool site for understanding optics in nature.
Opli Net - Cool grassroots optics magazine, forum and more!
optics2001.com - A subscription based site (?) for optics information.

Optics Bloggers and Researchers:
Idle Diffractions. Kevin Thompsons and ORA optics blog. Very good read.
Diehl Research Grant Services. Smart PhD Optics dude who actually enjoys writing proposals and helping others!!!
Optics the website. Awesome online calculators
Open Source Optics. Blogger that gives tutorials on Zemax programming language

Nomography: The graphical representation of mathematical relationships.
The art of nomography - part I of III. AWESOME website
PyNomo - a website for making nomographs with python
Geogebra - a graphical tool (geometry) for algebraic equations.

Other Fun Science!:
Periodic table of Periodic Tables. Thanks Margy (I think this was from her?)
Be sure to zoom in and click the links on the boxes.
Information is beautiful. Very awesome graphs. Thanks Deuard W for posting this in linkedin
Meta-Synthesis. Where was this guy when I was studying chemistry? Makes learning chem fun!