ioSafe's Solo USB hard drive is fireproof up to 1550 degrees and waterproof up to 10 feet for 3 days. ioSafe has taken a standard 500GB, 1TB or 1.5TB Seagate drive and encased in a fire/flood proof case. Here are some specs on the ioSafe Solo hard drives themselves or read the ioSafe Solo Datasheet (PDF). You can read about the various Disaster Recovery Service plans.
Watch the video below from CES2009 where the ioSafe people drop it in a swimming pool and set the unit on fire! the video is a little long (9 minutes) and you can tell the guy on the video likes to talk, but the demo is pretty cool.
More info: Creating a WHS disaster recovery plan