I'm currently developing a game for which I want to document my experience with online through my website. On the site, one of things I want to offer anyone who subscribes to my mailing list is access to my sourcecode repo via github. Basically, I want them to be able to play around with my source code for their own personal, educational use but I don't want them to be able to release any version of their own game from it, for profit or not. I found a creative commons license 'Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)' that seems to cover my goals. The only thing I'm unsure of is the 'NoDerivatives' portion. From what I understand this states no one can 'distribute' altered versions of the work but does this also imply that any modification for your own personal, educational use is okay? Or do I need to specify that explicitly on my site? If I do, can I just give universal approval by saying something like, "Though modification of the source code purely for your own, personal use is acceptable" after listing the creative commons license?
Looking at the license entry at Creative Commons, we see that the -ND means that "NoDerivatives — If you remix, transform, or build upon the material, you may not distribute the modified material." The actual (linked) license says that "produce and reproduce, but not Share, Adapted Material for NonCommercial purposes only.", which is the same thing in more formal language.
The license appears to do what you want it to do.
It is not a Free Software License as defined by the Free Software Foundation, nor an Open Source License as defined by the Open Source Initiative, which needn't concern you right now but which might come up in hosting sometime.