I was in the West of Ireland the other weeek on biz, and a strange mound in the middle of a field was pointed out to me.  The field was ploughed but this circular patch was left untouched, overgrown with bushes and whitethorn.  I was told it was a "fairy fort" (or "rath"), that they occurred all over Ireland and that no farmer would plough or disturb one for fear of reprisals from the fair folk.
A bit of research revealed that they are probably pre-Christian ring forts, and are said to be gateways to the underground world of the Aes Sidhe.  Perfect inspiration for the CBC celtic night!
Once again big thanks to Jude at Coconut Blues Club for setting another top challenge, and apologies to any Irish speakers out there for my disgraceful attempt at using the language.

Lyrics

A mile out of Draiocht Rath
In the dying sunset's splinters
Directly in his path
Stepped a girl of twenty winters.
And she was passing fair,
Silver haired and golden eyed
"Oh can you help me, sir?
I'm in sore distress" she cried.

So he slowed to hear the maid,
Keen to mend what made her suffer
Cruel fortune had dismayed
A promised errand for her dear father.
"Gladly I will" he said to her
"Tell me the dark secrets you're hiding".
"Pray tarry not, kind sir
And I'll tell thee as we're riding".

Now she was a wond'rous sight
Eldritch eyes and antique vesture.
The horses kicked and foamed with fright
'Til she calmed them with a gesture.
Off they rode, his heart aflame,
Still never a word said she.
"Can I not know your name?"
She replied: "Cailin na Sidhe".

Still he was athirst to learn
What her father had requested.
"He forbids me to return
Without a man's heart" she said.
"Oh, take mine!" he cried, intent
"And I will take you for my wife"
Too late he minded what she meant
As, from her cloak, she pulled the knife.

We laid him in an unmarked grave,
Where his name will fade from mention,
Guilty that his loss will save
The rest of us from Their attention.
We'll be safe from Draiocht Rath
For another twenty years.
And, like his wish, we know his heart's
Forever with Cailin na Sidhe.