gistfile1.txt

<%= f.input :kind, :as => :radio, :label => "Is this a single or multiple trip?", :collection => kinds_collection, :label_html => {:class => "inline"} %>

result.html

<div class="control-group radio_buttons optional">
  <label class="radio_buttons optional control-label inline">Is this a single or multiple trip?</label>
  <div class="controls">
    <label class="radio">
      <input class="radio_buttons optional" id="offer_kind_single" name="offer[kind]" type="radio" value="Single">Single
    </label>
    <label class="radio">
      <input class="radio_buttons optional" id="offer_kind_multiple" name="offer[kind]" type="radio" value="Multiple">Multiple
    </label>
  </div>
</div>