A basic sleep timer with a textual progress indicator (Note, not a progress bar)

Simple-SleepTimer.ps1

function Start-SleepTimer
{     
    param 
    (
        [Alias('s')]
        [int] $seconds
    )

    for($index = $seconds; $index -gt 0; $index--)
    {
        Write-Host "`rCountdown - $index seconds remaining" -NoNewline -ForegroundColor Yellow
        Start-Sleep -Seconds 1
    }

    # Note use of blank spaces to overwrite previous lines content
    Write-Host "`rCompleted $seconds second countdown.   " -ForegroundColor Yellow 
}

Start-SleepTimer -seconds 5