That's not good
Not sure what happened. The google spider may have tried to crawl the site when it was down for a while yesterday. When it couldn't access the site it temporarily (I hope!) removed the site from the listings. Next time the crawler does its thing the site will be back where it was before.
That's the good scenario.
The bad scenario is the site has been de-listed for some reason
Nick, thanks for the tips regarding the meta tags but search engines like Google don't rely on meta data in that way. They index the actual page content and do some other magical stuff which is what makes google google!
But I might update the tags anyway, they're well old.
Are you running Adsense on here?
Just thinking because there are a lot more adverts recently?
Or maybe you aint paid google enough money (no i'm not kidding)