Update:
We are dealing with a Denial of Service attack out of Asia.
http://en.wikipedia.org/wiki/Denial-of-service_attack
The short version (how I understood it) is that we are being hit over  and over, by thousands of malware infected computers, which is  overloading our servers and bringing the site down. We have people  working to block the attacking ips, during which time the site needs to  be completely offline. Once all of the ips have been blocked, we'll put  the site back up.
Thank you for your patience, it's been a rough day for everyone.
Always,
Gina