There's an interesting bi-lingual drama on TG4 at the moment. It's set in the Klondike at the end of the 19th Century, and concerns the adventures of the Connolly brothers in the Gold Rush town of Dominion.
Much of the interaction between the Irish inhabitants of Dominion is mainly in Irish (with subtitles), while they talk English to everyone else. The switching back and forth between languages is very natural, and works very well (though some of the Irish is easier to understand, and some of it is quite difficult).
The episodes are available on the TG4 website for 5 weeks after broadcast - the 4th episode was broadcast yesterday, so there are only 2 weeks left to watch the first episode.
The series was made in Ireland, and it's actually pretty convincing - though I'm sure that there must have been a bit more snow and ice in the Klondike :-).