Roman Haefeli strikes again: Watchteleboy makes it possible to watch dozens of live TV channels using mplayer in your very own machine, without the need for Flash, a web browser or any other such nonsense.
Here’s the source code: https://github.com/reduzent/watchteleboy
Here are Ubuntu packages he maintains: https://launchpad.net/~reduzierer/+archive/reduzent
Caveat: This only works if you’re located in Switzerland or in some other place that Teleboy’s geotargetting likes (such as Italy).