Could be a blip - how long have the serps been like this? The homepage is indexed and was cached on the 18th Nov. Looks like you have been busy building links - too many with the same anchor text can cause problems as I found out. Solution was to change the anchor text and build some authority backlinks. The site then bounced back.
What does your Google Webmaster account tell you? I heard about a similar case on WebmasterRadio. They brought up the topic and helped the webmaster resolve the issue. You should check it out!