I recently switched to IE9. Now when I go to a site with an expired or invalid SSL cert I am not presented with the option to continue to the site. I only get the option to close the browser/tab. The site I am going to is understood to have an invalid ssl by design for a specific reason -- so the answer to renew or get a valid certificate is not the answer here.
You will recall that in previous versions of IE the warning would be presented but you would be given the option to continue, acknowledging that you understood the risk, and even the option to get the cert and add it to the local store. I cannot figure out how to obtain the same level of functionality in IE9.