Powercli : get list of powered off virtual machines and date of shut down

Here is a good script that I came across

http://communities.vmware.com/message/2133377

The script connects to your vcenter or esxi host and checks to see if you have powered off vms and when they were powered off.

@"
===============================================================================
Title:         vminventory.ps1
Description:   Exports VM Information from vCenter into a .CSV file for importing into anything
Usage:         .\vminventory.ps1
Date:          10/15/2012
===============================================================================
"@

#### Get Virtual Center To Connect to:
$VCServerName= Read-Host "What is the Virtual Center name?"

$ExportFilePath = Read-Host "Where do you want to export the data?"

$VC = Connect-VIServer $VCServerName

$Report = @()

$VMs = get-vm |Where-object {$_.powerstate -eq "poweredoff"}
$Datastores = Get-Datastore | select Name, Id

$VMHosts = Get-VMHost | select Name, Parent

### Get powered off event time:
Get-VIEvent-Entity $VMs -MaxSamples ([int]::MaxValue) |
where {$_ -is [VMware.Vim.VmPoweredOffEvent]} |

Group-Object -Property {$_.Vm.Name} | %{
  $lastPO= $_.Group | Sort-Object -Property CreatedTime -Descending | Select -First 1

  $vm = Get-VIObjectByVIView -MORef $lastPO.VM.VM

  $report += New-Object PSObject -Property @{
    VMName = $vm.Name

    Powerstate = $vm.Powerstate

    OS = $vm.Guest.OSFullName

    IPAddress = $vm.Guest.IPAddress[0]
    ToolsStatus = $VMView.Guest.ToolsStatus

    Host = $vm.host.name

    Cluster = $vm.host.Parent.Name

    Datastore = ($Datastores | where {$_.ID -match (($vmview.Datastore | Select -First 1) | Select Value).Value} | Select Name).Name

    NumCPU = $vm.NumCPU

    MemMb = [Math]::Round(($vm.MemoryMB),2)
    DiskGb = [Math]::Round((($vm.HardDisks | Measure-Object -Property CapacityKB -Sum).Sum * 1KB / 1GB),2)
    PowerOFF = $lastPO.CreatedTime

    Note = $vm.Notes  }
}

$Report = $Report | Sort-Object VMName

if ($Report) {
  $report| Export-Csv $ExportFilePath -NoTypeInformation}
else{
  "No PoweredOff events found"

}

$VC = Disconnect-VIServer $VCServerName -Confirm:$False

Pasted from <http://communities.vmware.com/message/2133377#2133377>