atom_feed do |feed|
  @stories.each do |story|
    feed.entry story do |entry|
      entry.title story.title
      entry.content "<p>foo</p>", :text => "html"
    end
  end
end

curl produces:

<p>foo</p>

feedburner renders:

<p>foo</p>

I am assuming the curl needs to produce <p>foo</p> so that feedburner will render it correctly...