Homework – Double Digit Addition without Carrying
My son decided to pretend to be sick from school the other day, so after we finished all the work the teach gave us, I decided to make him some extra work. This code will generate a page with 25 double digit addition problems. They haven’t learn to carry over digits yet, so all sums are less than 10. Maybe someone else out there could get some benefits from it. 
[System.Collections.Generic.List[PSObject]] $page = @()
$j = 0
$blank52 = "<td height=""52""> </td>`n" * 9
$blank20 = "<td height=""20""><br></td>`n" * 9
while($j -lt 5){
    [System.Collections.Generic.List[PSObject]] $rowA = @()
    [System.Collections.Generic.List[PSObject]] $rowB = @()
    $i=0
    while($i -lt 5){
        $a = Get-Random -Minimum 1 -Maximum 10
        $b = Get-Random -Minimum 0 -Maximum (9-$a+1)

        $c = Get-Random -Minimum 1 -Maximum 10
        $d = Get-Random -Minimum 0 -Maximum (9-$c+1)

        if(($b + $d) -gt 0){
            if($b -eq 0){$b=' '}
            $rowA.Add("<td class=""xl66"" height=""52"" width=""115"">$a$c</td>`n")
            $rowB.Add("<td class=""xl65"" height=""52"" width=""115"">+ $b$d</td>`n")
            $i++
        }
    }

    $tableRows = New-Object System.Text.StringBuilder
    $tableRows.Append('<tr height="52">') | Out-Null
    $tableRows.Append($rowA -join('<td class="xl66" width="15"><br>')) | Out-Null
    $tableRows.Append('</tr><tr height="52">') | Out-Null
    $tableRows.Append($rowB -join('<td class="xl66" width="15"><br>')) | Out-Null
    $tableRows.Append("</tr><tr height=""52"">$blank52</tr>") | Out-Null
    $page.Add($tableRows.ToString())
    $j++
}


$bodyTop = @'
<html><head><title>math</title><style>.xl65{mso-style-parent:style0;font-size:36.0pt;mso-number-format:"\@";
text-align:right;border-top:none;border-right:none;border-bottom:1.5pt solid windowtext;border-left:none;}
.xl66{mso-style-parent:style0;font-size:36.0pt;mso-number-format:"\@";text-align:right;}</style></head><body>
<table style="text-align: left; width: 635px; height: 60px;" border="0" cellpadding="0" cellspacing="0"><tbody>
'@

$bodyBotton = @'
</tbody></table><br><br></body></html>
'@

$bodyTop + $page -join("<tr height=""20"">$blank20</tr>") + $bodyBotton | out-file '.\math.html'
  
Make Your Computer Talk 
Add-Type -AssemblyName System.Speech
$Speech = New-Object System.Speech.Synthesis.SpeechSynthesizer
$Speech.Speak("I'm sorry Dave, I'm afraid I can't do that")

Details

Use the built-in Speech Synthesizer to have PowerShell make your computer talk. Credit to u/urabusPenguin on r/PowerShell for the idea.

  
PowerShell Timer with Alarm 
Function Start-Timer {
    param(
    [Parameter(Mandatory=$true)]
    [int]$seconds,
    [Parameter(Mandatory=$false)]
    [switch]$alarm 
    )
    $a = $(Get-Date)
    For($i=1;$i -le $seconds;$i++){
        Write-Progress -Activity "$seconds Second Timer" -Status $i -PercentComplete $(($i/$seconds)*100) -id 1
        Start-Sleep -Seconds 1
    }

    if($alarm){
        For($i=1;$i -le 10;$i++){
            [console]::beep(500,300)
        }
    }
}

Details

Simply call the function with the number of seconds and the optional alarm switch. It will provide a countdown with a progress bar.