RailsFS
why is one of my personal heroes. You can simply throw a handful of half-formed ideas at him, and he turns around and puts them together in the most astonishing and gratifying ways.
Today, he demonstrates using FUSE, via its Ruby binding, to mount your Rails database as a filesystem.
Once mounted, this gets you a directory for each table, populated with YAML files, one for each record. Edit one in vi. Save. Database update. All the usual Unix things.
Heck, you can back up your database with tar.