this will stream tv episodes in your web browser (over the internet) from Comcast web site
http://xfinitytv.comcast.net/full_episodes#core=locked
the following Cable Card devices use the Cable Tv channels you subscribe to and replace or act as additional tv cable boxes that connect to & display on a PC, including any premium channels you subscribe to.
http://www.silicondust.com/products/hdhomerun/prime/
http://cetoncorp.com/products/infinitv/
http://www.hauppauge.com/site/products/data_dcr2650.html