in reply to What's your prefered revision control system?

i use cp -rp, but i'd love to switch to something a bit more professional, but lack the time and discipline to do everything in a full-fledged RCS, i fear.
So, does anyone know of a completly transparent versioning system? e.g. an FTP server that instead ov overwriting files, saves timestamped backups somewhere, or a filesystem that does something like that?