Shakespeare is, in one sense at least, like dessert: there's always room for a little Shakespeare.
Although it took until almost the last moment in Season Three, the British Comedy Drama Doc Martin finally squeezed in a little.
There may be more later on, but I haven't yet watched much further than that point—for example, Season four, episode two bears the title "Uneasy Lies the Head," a quote from 2 Henry IV (if you're keeping track, it's III.i.31), and I hold out great hope for additional Shakespeare.
But one line (a quote from Henry V—III.i.1, if you're keeping track) is all we get in this one. A reluctant priest has been convinced to return to the church for one last service. Here's what he says upon entry:
"Once more unto the breach, dear friends!" (Henry V, III.i.1)
And that's all—at least for now!
Links: The Episode at IMDB. Watch the Episode at Hulu.