I regularly watch the videos provided by Tedtalks. But this is only O.K. when you are using a browser. If you want to save the videos for later viewing you have to download them a second time. I stumbled upon a program called podracer. This little tool enables you to provide a list of RSS feeds that then read and all media that is provided in the feed gets downloaded. Ad a small cron job to the mix and you can use MythTV to watch all the latest Tedtalks.

RSS feed from Tedtalks: http://feeds.feedburner.com/TedtalksHD?format=xml

To install podracer on Ubuntu just type: sudo apt-get install podracer

Then edit the .podcaste/subscriptions file by adding the above RSS feed link.

run podracer or add a cronjob. Enjoy.