A PowerShell function to display an event countdown.

Get-EventCountdown.ps1

#requires -version 5.1

Function Get-EventCountdown {
    [cmdletbinding()]
    [OutputType("PSCountdown")]
    Param(
        [Parameter(Position=0,Mandatory,ValueFromPipeline,ValueFromPipelineByPropertyName,HelpMessage = "Enter the event date and time.")]
        [ValidateNotNullOrEmpty()]
        [ValidateScript({
            if ($_ -ge (Get-Date)) {
                $True
            }
            else {
                Write-Warning "The specified events date has already occurred."
                Throw "You must specify a future datetime."
                $false
            }
        })]
        [alias("Date")]
        [datetime]$EventDate,
        [Parameter(Mandatory,ValueFromPipelineByPropertyName)]
        [ValidateNotNullOrEmpty()]
        [alias("Name")]
        [string]$EventName
    )
    Begin {
        Write-Verbose "[$((Get-Date).TimeofDay) BEGIN  ] Starting $($myinvocation.mycommand)"
    } #begin

    Process {
        Write-Verbose "[$((Get-Date).TimeofDay) PROCESS] Getting event countdown for $eventName [$EventDate]"
        $ts = New-Timespan -Start (Get-Date) -End $EventDate

        [PSCustomObject]@{
            PSTypename = "PSCountdown"
            EventName = $EventName.Trim()
            EventDate = $EventDate
            Countdown = $ts
        }
    } #process

    End {
        Write-Verbose "[$((Get-Date).TimeofDay) END    ] Ending $($myinvocation.mycommand)"
    } #end

} #close Get-EventCountdown

# Set variables to control formatting based on the number of days
# before an event is scheduled. These values are using the format.ps1xml file

#events almost here
$PSCountdownCritical = 7
#events getting closer
$PSCountdownPending = 14

Update-Formatdata $PSScriptRoot\pscountdown.format.ps1xml

pscountdown.format.ps1xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
Format type data generated 04/30/2021 09:33:14 by PROSPERO\Jeff

This file was created using the New-PSFormatXML command that is part
of the PSScriptTools module.
https://github.com/jdhitsolutions/PSScriptTools
-->
<Configuration>
  <ViewDefinitions>
    <View>
      <!--Created 04/30/2021 09:33:14 by PROSPERO\Jeff-->
      <Name>default</Name>
      <ViewSelectedBy>
        <TypeName>PSCountdown</TypeName>
      </ViewSelectedBy>
      <TableControl>
        <!--Delete the AutoSize node if you want to use the defined widths.
        <AutoSize />-->
        <TableHeaders>
          <TableColumnHeader>
            <Label>EventName</Label>
            <Width>35</Width>
            <Alignment>left</Alignment>
          </TableColumnHeader>
          <TableColumnHeader>
            <Label>EventDate</Label>
            <Width>30</Width>
            <Alignment>left</Alignment>
          </TableColumnHeader>
          <TableColumnHeader>
            <Label>Countdown</Label>
            <Width>13</Width>
            <Alignment>right</Alignment>
          </TableColumnHeader>
        </TableHeaders>
        <TableRowEntries>
          <TableRowEntry>
            <TableColumnItems>
              <TableColumnItem>
                <ScriptBlock>
                If ($host.name -match "console") {
                  if ($_.countdown.totaldays -le $PSCountdownCritical) {
                       "$([char]27)[91m$($_.EventName)$([char]27)[0m"
                  }
                  elseif ($_.countdown.totaldays -lt $PSCountdownPending) {
                        "$([char]27)[93m$($_.EventName)$([char]27)[0m"
                  }
                  else {
                    $_.EventName
                  }
                }
                else {
                 $_.EventName
                }
                </ScriptBlock>
              </TableColumnItem>
              <TableColumnItem>
                <ScriptBlock>
                If ($host.name -match "console") {
                  if ($_.countdown.totaldays -le $PSCountdownCritical) {
                       "$([char]27)[91m$($_.EventDate)$([char]27)[0m"
                  }
                  elseif ($_.countdown.totaldays -lt $PSCountdownPending) {
                        "$([char]27)[93m$($_.EventDate)$([char]27)[0m"
                  }
                  else {
                    $_.EventDate
                  }
                }
                else {
                 $_.EventDate
                }
                </ScriptBlock>
              </TableColumnItem>
              <TableColumnItem>
                <ScriptBlock>
                  $cd = $_.Countdown.ToString("dd\.hh\:mm\:ss")

                If ($host.name -match "console") {
                  if ($_.countdown.totaldays -le $PSCountdownCritical) {
                       "$([char]27)[91m$($cd)$([char]27)[0m"
                  }
                  elseif ($_.countdown.totaldays -lt $PSCountdownPending) {
                        "$([char]27)[93m$($cd)$([char]27)[0m"
                  }
                  else {
                    $cd
                  }
                }
                else {
                 $cd
                }
                </ScriptBlock>
              </TableColumnItem>
            </TableColumnItems>
          </TableRowEntry>
        </TableRowEntries>
      </TableControl>
    </View>
  </ViewDefinitions>
</Configuration>

These files are described at https://jdhitsolutions.com/blog/powershell/8357/friday-fun-counting-down-events-with-powershell/