My exercise in how small you can make a version-control system and still have it be useful, src, does seem to have a significant if quiet fanbase out there. I can tell because patches land in my mailbox at a slow but steady rate.
As the blurb says: Simple Revision Control is RCS/SCCS reloaded with a modern UI, designed to manage single-file solo projects kept more than one to a directory. Use it for FAQs, ~/bin directories, config files, and the like. Features integer sequential revision numbers, a command set that will seem familiar to Subversion/Git/hg users, and no binary blobs anywhere.