Update: I have started a project called Fox SIS that will be based off of a once-prominent open source student information system. Please see the blog post and use the comment form on that post to let me know if you would be interested in participating. Comments will be closed for this post. Please post any questions to the Fox-SIS Forum.
Main Article
Focus SIS is an open source student information system hosted at source forge that I was involved with back when I worked at a small school district. I at one time had the download available here, but have been asked by the folks at focus-sis.org to remove it. I will instead, provide instructions on how to download the project named focus-sis from source forge.
Let me disclaim quickly: This is not the software that is available as a service from focus-sis.org although the commercial version spawned from this project. The software available at focus-sis.org is most assuredly more stable, polished and feature-rich than the older, legacy version hosted on source forge.
These are instructions on how to download the GPL project known as focus-sis on source forge.
Windows:
Download TortiseSVN from http://tortoisesvn.net/downloads and follow installation instructions
Make a new folder and name it something like SIS.
Right click on that folder and select SVN Checkout.
Enter this url for the repository: https://focus-sis.svn.sourceforge.net/svnroot/focus-sis/branches/2.3/
Click OK
Linux
Run (assuming ubuntu or debian - if you are using something else, you can figure it out)
# sudo apt-get install subversion
# svn co https://focus-sis.svn.sourceforge.net/svnroot/focus-sis/branches/2.3/ sis
This will create a new folder called sis in the current directory with the source code in it.