Version control without internet?

[RoboMaster]

I'm wondering if there's any options out there for version control/collaboration but doesn't require an internet connection (ex. not SVN). Our programming computer can't really be hooked up to the internet when we're working at school.

Currently, sometimes one of us brings their own computer and we work on different things at the same time. Then we copy the part of the code to be worked on onto the other computer and replace it when the work is done. (We use LabVIEW so copying and replacing subVIs is easy). Plus, we plan to work at home more this year. For backups, we copy the whole LabVIEW project into a folder and put that on our team's external hard drive.

But of course it's always nice to have a good versioning software or method. Does anyone know of anything out there? Thanks!