### So you can pass the clock file ...
param($clockxaml="clock.xaml")

### Import the WPF assemblies
Add-Type -Assembly PresentationFramework
Add-Type -Assembly PresentationCore

Write-Host "Initializing Performance Counters, please have patience" -fore Cyan
$script:cpu = new-object System.Diagnostics.PerformanceCounter "Processor", "% Processor Time", "_Total"
$script:ram = new-object System.Diagnostics.PerformanceCounter "Memory", "Available KBytes"

## get initial values, because the counters don't work until the second call
$null = $script:cpu.NextValue()
$null = $script:ram.NextValue()
$script:maxram = (gwmi Win32_OperatingSystem).TotalVisibleMemorySize

Write-Host "Loading XAML window..." -fore Cyan
## I've removed the xaml to a separate document because it's getting too big for my example :)

$clock = [Windows.Markup.XamlReader]::Load( 
         (New-Object System.Xml.XmlNodeReader (
            [Xml](Get-Content $clockxaml) ) ) )

## Create a script block which will update the UI
$counter = 0;
$updateBlock = {
   # Update the clock
   $clock.Resources["Time"] = [DateTime]::Now.ToString("hh:MM.ss")

   # We only want to update the counters at most once a second
   # Otherwise their values are invalid and ...
   # The CPU counter fluctuates from 0 to the real number
   if( $counter++ -eq 4 ) {
      $counter = 0
      # Update the CPU counter
      $cu = $cpu.NextValue()
      $clock.Resources.CpuP = ($cu / 100)
      $clock.Resources.Cpu = "{0:0.0}%" -f $cu
      #$clock.FindResource("CpuStory").Begin($clock)
      # Update the RAM counter
      $rm = $ram.NextValue()
      $clock.Resources.RamP = ($rm / $maxram)
      $clock.Resources.Ram = "{0:0.00}Mb" -f ($rm/1MB)
      #$clock.FindResource("RamStory").Begin()
      }
}

## Hook up some event handlers 
$clock.Add_SourceInitialized( {
   ## Before the window's even displayed ...
   ## We'll create a timer
   $timer = new-object System.Windows.Threading.DispatcherTimer
   ## Which will fire 4 times every second
   $timer.Interval = [TimeSpan]"0:0:0.25"
   ## And will invoke the $updateBlock
   $timer.Add_Tick( $updateBlock )
   ## Now start the timer running
   $timer.Start()
   if( $timer.IsEnabled ) {
      Write-Host "Clock is running. Don't forget: RIGHT-CLICK to close it."
   } else {
      $clock.Close()
      Write-Error "Timer didn't start"
   }
} )

$clock.Add_MouseLeftButtonDown( { 
   $_.Handled = $true
   $clock.DragMove() # WPF Magic!
} )
$clock.Add_MouseRightButtonDown( { 
   $_.Handled = $true
   $timer.Stop()  # we'd like to stop that timer now, thanks.
   $clock.Close() # and close the windows
} )

## Lets go ahead and invoke that update block 
&$updateBlock
## And then show the window
$clock.ShowDialog()