This powershell script will enumerate the Git projects in a parent directory, perform a fetch on each remote and then print out the status of the repo.

git-all.ps1

$global:GitAllSettings = New-Object PSObject -Property @{
	FolderForegroundColor       = [ConsoleColor]::Cyan
}

function git-all()
{
	$s = $global:GitAllSettings
	dir -r -i .git -fo | % {
		pushd $_.fullname
		cd ..
		write-host -fore $s.FolderForegroundColor (get-location).Path
		git-fetchall
		popd
	}
}

function git-fetchall()
{
	$remotes = git remote
	if($remotes){
		$remotes | foreach {
			Write-Host 'Fetching from' $_
			git fetch $_
		}
	}else{
		Write-Host 'No remotes for this repository'
	}
	git status
}

[System.Reflection.Assembly]::LoadWithPartialName("System.Diagnostics")

$sw = new-object system.diagnostics.stopwatch
$sw.Start()

git-all

$sw.Stop()
Write-Host "Completed in " $sw.Elapsed