gistfile1.rb

def available?(order)
  special_categories = ShippingCategory.find(:all, :conditions => ["name IN ('TV', 'Medium Size TV', 'Oversized TV')"])        
  order.line_items.each do |line_item|
    product = line_item.variant.product
    return false if special_categories.include?(product.shipping_category)
  end                                                                    
  true
end