Is there a plugin that will auto generate Meta Descriptions?

Hi there,

So what I am looking for is a plugin that will auto generate the meta description of all my page meta descriptions? I have a page with about 100 pages and they all have an identical meta description. I'd really like to mix it up a bit for SEO purposes but going back and doing it manually is way too time-consuming. Does anyone know of an automated process for this - preferably one that can incorporate my targeted search keywords?