I nearly commented before about similarities in format between JSON and REBOL, (my language of choice), but I didn't. But I've just watched a video of a talk JSON's designer gave on the history of JSON, and he mentioned REBOL as an influence, so I wasn't just seeing things! It's a good talk too, so have a look if you've not already seen it...

http://developer.yahoo.com/yui/theater/video.php?v=crockford-json

A full transcript's there too.

(REBOL's problem is it isn't open-source - makes you weep, it does.)