Some parts are dreamhost centric.
Is it down just for me:
1/ ssh to another machine and: $ ping thedomain.com
2/ http://downforeveryoneorjustme.com/
Dreamhost status:
1/ http://www.dreamhoststatus.com/
2/ schedule tests
DNS status:
$ whois thedomain.com (check that the name servers are ns1.dreahmost.com, ns2.dreahmost.com, ns3.dreahmost.com)
$ host thedomain.com
$ dig thedomain.com
$ traceroute thedomain.com