Some of the dreamhost servers seem to be flakey. In the last hour or two, there's about a 50% chance of things failing with the message below. Hitting refresh a few times tends to fix this. Dreamhost support has been pinged.
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, email@example.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
UPDATE Dreamhost says they've rebooted a server, and there should be no further issues.