<% @objects.each do |object| %>
['<%= link_to(object.user.name, user) %>',
'<%= object.description || "-" %>',
'<%= object.created_at %>'
],

extracted.. "By far the most common error I’ve encountered relates to object keys. In JSON (unlike in JavaScript) these MUST be double-quoted strings. In fact, ALL strings in JSON must be enclosed in double quotes (JavaScript also allows single quotes; JSON does not)."

Valid:

{ "name": "Simon" }

Invalid:

{ name: "Simon" }
{ 'name': "Simon" }
{ "name": 'Simon' }
http://simonwillison.net/2006/oct/11/json/