LOVE this thread! Well done Schmick!

My DS is too young to mess with his head yet (but looking forward to it ) but we have a number of nieces & nephews which we've tormented for years.

Once my nephew didn't want to be outside with the rest of us but was only about 3 and couldn't be trusted inside on his own. So DH started saying 'did you see that shark in the lawn?' and kept him busy for hours with watching for the sharks in the lawn. It still gets talked about amonst the family!

DS also had the nieces almost convinced that he eats budgies & parrots... so they stopped asking if we wanted one!

Also, the kids favourite bunny rabbit escaped (or died - can't remember now) about a week before easter one year. SIL couldn't bring herself to tell the kids so she got DH to write a letter from the Easter Bunny saying that he needed their rabbit to help deliver the eggs this easter. The kids believed it so well that we had to write letters from the rabbit for about 5 years giving updates on how the rabbit was doing! DH is very creative and he did it up with glitter and stamped a bunny footprint in it and we put talcum powder around where it was left, etc.

I hope to do the one about 'the car won't start until the seatbelts are done up' too, but my MIL has a shocking habit of starting the car while she's standing outside of it and then puts on the seatbelt down the road while she's driving. I've tried to disuade her from doing this, but she's well set in her ways now! Maybe I'll be able to convince him that OUR car won't start...