This is one I tell in our ghost story program...

Angus's long-suffering wife was fed up with her husband's unfortunate fondness of a not-so-wee dram. Most evenings he would roll home from the pub considerably the worse for wear. His wife resolved to cure him. Late one All Hallows' Eve, she put a bedsheet over her head, hid behind the bushes at the front door of their croft, and waited for her wayward hubby to come home. Eventually Angus staggered up the path.

His wife, in disguise, jumped out from behind the bushes, and cried out, "Angus! I'm the Devil! And I've come to warn ye ..."

"The Devil, you say?" Angus interrupted. "Then ye must come in and have a dram wi' me, kinsman. I do believe I'm married to your sister!"