Okay, ‘sneaky’s’ probably not the right word.
David Malki of Wondermark has an idea—why not send your left over Christmas cards to total strangers?
He recognises there are risks involved, for the person receiving the card as well as sending it. And you’ll probably never know what the effect of the surprise will be. Still, it can be fun.
I recommend writing a warm, perfectly normal note (no “Thanks for the backrub last night” or “The aliens are after you”), and for maximum puzzlement, enclosing a brief family newsletter. Again, the aim is to be perfectly banal and typical, with nothing to show your hand that you don’t know these people.
A touch of the weird is fine. Your newsletter can talk about your accordion concert tour across Bulgaria. But keep it subtle.
Let us know how you go.