rss-download.ps1

 # Edit the following variable as required. 
 $destination="F:\Media\Build2014\"
 $list = "F:\Media\Build2014\episodes.txt"
if(!(test-path($destination))){
  New-Item $destination -ItemType directory
}
if((test-path($list))) {
  $grabbed = get-content $list
} else {
  New-Item $list -type file
  $grabbed = @()
}

# This is the initial part of the URL for the WMV High videos. (this is a comma separated list of feeds)
@("http://s.ch9.ms/Events/Build/2014/RSS/mp4high","http://s.ch9.ms/Events/Build/2014/RSS/mp4")|foreach{
  $rss=invoke-webrequest -uri $_
  [xml]$rss.Content|foreach{ 
    $_.SelectNodes("rss/channel/item/enclosure") 
  }|where { 
   # only if it does not exist in the episodes file
   $grabbed -notcontains($_.url.split("/")[-1])
  }|foreach{   
    $fn = $_.url.split("/")[-1]
    $ext = $fn.split(".")[-1]
    $title = $_.ParentNode.SelectSingleNode("title/text()").Value.Replace(":","-").Replace("+","_").Replace("\\","_").Replace("/","_").Replace("?","_").Trim()
    # even if it is not in the episodes file, if the destination exists, it will be skipped.
    if(!(test-path ($destination + $title + "." + $ext))){ 
      "Downloading: " + $title + " : " + $fn.split(".")[0]
      $out = $destination + $title + "." + $ext
      start-bitstransfer $_.url $out
      Out-File $list -Append -InputObject $fn
      start-sleep -seconds 30 
    } 
  }
}