My most memorable white lie was orchestrated on a crisp, frosty Christmas Eve many moons ago when our children were just getting to the age when they began to question the Father Christmas myth.
We did the usual rituals of setting out a mince pie and drink for Father Christmas and putting some carrots and a bowl of water outside for the reindeer. When they were both tucked up in bed and the presents were laid out ready for the big reveal on Christmas morning, we went outside to remove the carrots, tip out some of the water and add some blades of grass to make it look as if the reindeer had been drinking from the bowl. I then had an idea designed to help keep the magic alive. We'd make sleigh tracks on the frosty lawn using two planks of wood.
Sure enough, on Christmas morning, our little white lie was swallowed hook, line and sinker and we could have a magical Christmas for at least one more year.