When I was little, my two cousins and I usually spent the holidays with each other's families in turn. The three of us slept in one big bed. We kept each other awake most of the night, talking about the mysteries and wonders of Christmas morning. Our stockings were always huge and in the morning when we woke, the first thing we did was check what was inside.
One Christmas Eve I woke at the critical moment, and saw, not Santa Claus, but three familiar figures hissing from the doorway 'Hurry up - don't wake them!' I lay as still as death. Next morning I shattered the already somewhat shaky illusions of my two cousins. We told no one what we knew, and kept our secret for a year.
The following Christmas Eve we laid a Santatrap. This consisted of a collection of kitchen utensils - saucepans laid in strategic positions on the floor, a baking tin filled with forks and spoons balanced on the top of the floor, kettles hung from the ceiling. We kept awake until at last we heard the sound of footsteps from the stairs, accompanied by 'shushes' from the aunts. The trap worked beautifully. The uncles and my father, merry and unsuspecting, after an evening's celebration, were approaching with their sacks of presents. As they pushed the door open, the tins and cutlery crashed round their ears. Pushed forward by the screaming aunts, they fell over the pots and pans and bumped into the hanging kettles. The lights went on. We leapt up and jumped on them, screaming in triumph, ending the happy myth with a bang.
The L-shaped Room by Lynne Reid Banks)