My friend usagijer tipped me off to a new item on SourceForge: TiVo2DVD.
Tivo2dvd creates and executes the series of commands required to access, format, and burn television shows from a Series II Tivo directly to a DVD. It supports processing multiple shows at once, to a DVD with menus.
As the man page says:
tivo2dvd is a command-line script which automates the process of fetching television programs off of a Series II Tivo device, processing them, and burning them to a DVD.
To use TiVo2DVD you must have the prerequisites installed: perl, curl, Net::Tivo, tivodecode, transcode, mjpegtools, and tovid.
Technically it is supposed to run on any POSIX OS, so you could probably get this to work on MacOS, and even Windows. But this is definitely not something for non-geeks.