A Hyper-V virtual machine has been made available by Microsoft which contains SQL Server Denali CTP3 + SharePoint 2010 + Office 2010. I downloaded each part, extracted them, imported my VM, and launched it for the first time with great anticipation.
Then things came to a screeching halt: Cannot connect to the configuration database. This message was displayed when I tried to launch the "SQL Server - Home" link on its desktop. Central Admin had the same error.
To resolve: go to Services (Start > Administrative Tools > Services) and start the SQL Server service for the POWERPIVOT instance. Although it's set to be automatic, it's apparently not.
Also, I found I needed to restart the VM twice. If starting the SQL services doesn't work for you & you've only rebooted once, try one more reboot + starting of the SQL service. That sequence of events worked for me.