function Get-FirstMondayOfMonth

function Get-FirstMondayOfMonth
    {
    <#
    comment based help goes here
    #>

    [CmdletBinding ()]
    Param (
        [Parameter(
            Position = 0
            )]
            [ValidateRange (1,12)]
            [int]
            $MonthNumber = (Get-Date).Month
        )

    if ($MonthNumber)
        {
        $Day_1 = Get-Date -Month $MonthNumber -Day 1
        }
        else
        {
        $Day_1 = Get-Date -Day 1
        }

    switch ($Day_1.DayOfWeek.value__)
        {
        0 {
            $Offset = 1
            break
            }
        1 {
            $Offset = 0
            break
            }
        default {
            # the "+ 1" is to handle the "off-by-one" array index difference
            $Offset = 7 - $Day_1.Date.DayOfWeek.value__ + 1
            }

        }

    $Day_1.Date.AddDays($Offset)

    }