Just found the classics section, have to share this. It's my mum's, and dad only admitted to me very recently, after a few pints, that it was in fact true.
Around 2am, mum, who's been contracting on and off all day with DC3, reckons enough is enough. Nudges dad. 'Love, baby's coming'. Dad rolls over. So mum, who kind of wanted a home birth anyway, leaves him to sleep. Around 6 am, waters break. Mum nudges dad. 'Love, BABY'S COMING!'. Dad rolls over. About 8am, mum gets dad to ring his father to come and look after other kids while they go in to hospital. On the phone:
Dad: 'LRDmum thinks she's, er, having the baby!'
Dad's dad: 'Are you sure?'
Dad: 'No, actually. Between you and me, I think it's a false alarm.'
Dad'sdad: 'Ah well, we'll humour her...'
Mum (listening in): 'AAAARRRRRGHHHHHHHH!'
Little brother arrived in the hospital corridor.
Dad never admitted he had this conversation all the time I was growing up - mum repeatedly claimed he had and he had the nerve to say she'd dreamed it all. But he has admitted it now.
Oh, and dad's dad managed to 'help' by putting a wash on with soap flakes instead off powder, thereby rendering them washing machine-less with a newborn.