This is an sample application for reading RSS feeds converted to JSON format. I used my Minimal River.js Reader as a baseline. This is a reader for reading an individual feed, but it is wrapped in the same JSONP wrapper as River.js feeds.
You can see the app running at http://andysylvester.com/files/reader_rssjs/
This blog post also talks about the app.
https://github.com/andysylvester/minimal-riverjs-reader/ - Minimal River.js Reader
http://rssjs.org/ - Website for rss.js format
http://www.w3schools.com/json/json_eval.asp - Using JSON objects
http://api.jquery.com/jQuery.ajax/ - jQuery docs for the .ajax request handler