My personal preferred suggestion: the Bittorrent Channel for Plex[0]. Plex is, effectively, a media indexing, library management, and transcoding daemon, that also provides plug-ins (Channels) to access virtual media items. In this setup, you have a streaming player (e.g. a Roku) and a PC running Plex--you access the torrent through the interface on the media player, and the PC will start downloading and transcoding the torrent and streaming the result to the media player.

[0] https://forums.plex.tv/index.php/topic/102253-rel-bittorrent...