Today I needed a script to give me the last created site collections.
I found a reference here. I modified it a little bit so that it actually works and disposals are being done the right way …

$siteUrl = "<Absolute Url Pointing to a Site Collection in your WebApp>"
$date = date
$timeInHistory = ($date.AddDays(-5))

#  Load Snapins
Try
{
	@('Microsoft.SharePoint.PowerShell') | % {
		   $snapinName = $_
		   if ((Get-PSSnapin | ? {$_.Name -eq $snapinName}) -eq $null)
		   {
				  Write-Host "Adding PSSnapin $snapinName"
				  Add-PSSnapin $snapinName
		   }
	} 
}
Catch
{
	Write-Host "Error adding Snapin for SharePoint" -foregroundcolor Black -backgroundcolor Red
    return
}
Write-Host ""

$rootSite = $null
$site = $null
$web = $null

 try
 {
	$rootSite = New-Object Microsoft.SharePoint.SPSite($siteUrl)
	$spWebApp = $rootSite.WebApplication
	foreach($site in $spWebApp.Sites)
	{
		foreach($web in $site.AllWebs)
		{
		   if(($web.created -ne $null) -and ($web.created -gt $timeInHistory))
		   {
				[string]$output = $web.url + "      " + $web.created.ToShortDateString()
				write-host $output
		   }
		   $web.Dispose()
		}
		$site.Dispose()
	}
	$rootSite.Dispose()
}
finally
{
	if ($web -ne $null) { $web.Dispose() }
	if ($site -ne $null) { $site.Dispose()}
	if ($rootSite -ne $null) { $rootSite.Dispose()}
}