Ard.de videos are very easy to get.

Try to find the Windows Media stream URL with freeware URL Snooper. Then you may use freeware SDP Receiver or FlashGet to record them.

You may also find stream URLs with WM Recorder. But if if you record Windows Media streams with other media stream recorders you may need to change http:// onto mms:// or rtsp://.

Not all of the web-site are that easy. Thay is why I recommend WM Recorder. It can record more Windows Media streams than any other stream recorder.