Little Herbie had been blind since birth. One day at bedtime, his mother told him that the next day was a very special one. If he prayed extra hard, he'd be able to see when he woke up in the morning.
The next morning she came into Herbie's room to make sure he'd prayed hard the night before.
'Well then, open your eyes and you'll know that your prayers have been answered.'
Little Herbie opened his eyes, only to cry out, 'Mother! Mother! I still can't see!'
'I know, dear,' said his mother. 'April Fool!'