From: Patrick Maupin on
RSON (Readable Serial Object Notation) is a superset of JSON that is
suitable for files that humans have to edit and diff.

The current release is decoder-only, but the decoder will read files
encoded by JSON encoders such as json or simplejson.

The current release consists of a single Python module and a short
manual. The manual admittedly needs some work, but has a few syntax
examples.

http://code.google.com/p/rson/