version 1

####### Launch as : ##########################
## powershell.exe -sta -file .\balloon.ps1  ##
##############################################

Write-Host -ForeGround Yellow " ###### START OF SCRIPT ! ######"
[void][System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

$Title = "This is the title"
$Text = "This is the text"
$EventTimeOut = 5

$balloon = New-Object System.Windows.Forms.NotifyIcon
$balloon.Icon = [System.Drawing.SystemIcons]::Information
$balloon.BalloonTipTitle = $Title
$balloon.BalloonTipText = $Text
$balloon.Visible = $True

$balloon.ShowBalloonTip(1)

Register-ObjectEvent $balloon BalloonTipClicked -SourceIdentifier event_BalloonTipClicked `
    -Action {
        # explorer.exe; `
        Write-Host  -ForeGround Green "event_BalloonTipClicked occured !"; `
        # Gets rid of icon
        $balloon.Dispose(); `
    }|Out-Null

Register-ObjectEvent $balloon BalloonTipClosed -SourceIdentifier event_BalloonTipClosed `
    -Action {
        Write-Host -ForeGround Green "event_BalloonTipClosed occured !"; `
        $balloon.Dispose(); `
    }|Out-Null 

Wait-Event event_BalloonTipClicked -TimeOut $EventTimeOut
Wait-Event event_BalloonTipClosed -TimeOut $EventTimeOut

Unregister-Event -SourceIdentifier event_BalloonTipClicked
Unregister-Event -SourceIdentifier event_BalloonTipClosed

Write-Host -ForeGround Gray "Should be empty -- start --"
Get-EventSubscriber
Write-Host -ForeGround Gray "Should be empty -- end --"

#[System.Windows.Forms.MessageBox]::Show("Done !!")
Write-Host -ForeGround Yellow " ###### END OF SCRIPT ! ######"

version 2

####### Launch as : ##########################
## powershell.exe -sta -file .\balloon.ps1  ##
##############################################

Write-Host -ForeGround Yellow " ###### START OF SCRIPT ! ######"
Add-Type -Assembly System.Windows.Forms

$Title = "This is the title"
$Text = "This is the text"

$balloon = New-Object System.Windows.Forms.NotifyIcon -Property @{
    Icon = [System.Drawing.SystemIcons]::Information
    BalloonTipTitle = $Title
    BalloonTipText = $Text
    Visible = $True 
}

$balloon.ShowBalloonTip(1)


$null = Register-ObjectEvent $balloon BalloonTipClicked -SourceIdentifier event_BalloonTipClicked -Action {
        Write-Host  -ForeGround Green "event_BalloonTipClicked occured !"        
        Unregister-Event -SourceIdentifier $event.SourceIdentifier -Force
        Remove-Job $event.SourceIdentifier -Force

        # unregister event and remove job object
        Unregister-Event -SourceIdentifier event_BalloonTipClosed -Force
        Remove-Job event_BalloonTipClosed -Force

        $balloon.Dispose()
}

$null = Register-ObjectEvent $balloon BalloonTipClosed -SourceIdentifier event_BalloonTipClosed -Action {
        Write-Host -ForeGround Green "event_BalloonTipClosed occured !"
        Unregister-Event -SourceIdentifier $event.SourceIdentifier -Force
        Remove-Job $event.SourceIdentifier -Force

        # unregister event and remove job object
        Unregister-Event -SourceIdentifier event_BalloonTipClicked -Force
        Remove-Job event_BalloonTipClicked -Force

        $balloon.Dispose()
}

related

###################################################
## Launch as :                                   ##
## cmd /k powershell -Sta [-File] .\balloon.ps1  ##
###################################################


# This post put me on the right track "http://social.technet.microsoft.com/Forums/en-US/winserverpowershell/thread/10983ec3-7aa6-4011-a87e-a30a25ab484a/"

Write-Host -ForeGround Yellow " ###### START OF SCRIPT ! ######"
[void][System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

$Title = "This is the title"
$Text = "This is the text"
$EventTimeOut = 5

$balloon = New-Object System.Windows.Forms.NotifyIcon -Property @{
    Icon = [System.Drawing.SystemIcons]::Information
    BalloonTipTitle = $Title
    BalloonTipText = $Text
    Visible = $True
}

# Value "1" here is meaningless. $EventTimeOut will force bubble to close.
$balloon.ShowBalloonTip(1)

Register-ObjectEvent $balloon BalloonTipClicked -SourceIdentifier event_BalloonTipClicked
Register-ObjectEvent $balloon BalloonTipClosed -SourceIdentifier event_BalloonTipClosed

# "Wait-Event" pauses the script here until an event_BalloonTip* is triggered
# TimeOut is necessary or balloon and script hangs there forever. 
# This could be okay but event subscription gets messed up by following script instances generating the same event names1.
$retEvent = Wait-Event event_BalloonTip* -TimeOut $EventTimeOut

# Script resumes here.
$retSourceIdentifier = $retEvent.SourceIdentifier
If ($retSourceIdentifier -eq $null){
    Write-Host  -ForeGround Green "TimeOut occured !"
}Else{
    Write-Host  -ForeGround Green "$retSourceIdentifier occured !"
    }

If ($retSourceIdentifier -eq "event_BalloonTipClicked"){
    explorer.exe
    }

# Gets rid of icon. This is absolutely necessary, otherwise icon is stuck event if parent script/shell closes
$balloon.Dispose()

# Tidy up, This is needed if returning to parent shell.
Unregister-Event -SourceIdentifier event_BalloonTip*
Get-Event event_BalloonTip* | Remove-Event
Write-Host -ForeGround Gray "Should be empty -- start --"
Get-EventSubscriber
Write-Host -ForeGround Gray "Should be empty -- end --"

#[System.Windows.Forms.MessageBox]::Show("Done !!")
Write-Host -ForeGround Yellow " ###### END OF SCRIPT ! ######"