What number comes next?

This man was sitting quietly reading his paper one morning, peacefully enjoying himself, when his wife sneaks up behind him and swacks him on the back of his head with a huge frying pan.

He asks, 'What was that for?'

She replies, 'What was that piece of paper in your pants pocket with the name Marylou written on it?'

He says, 'Oh honey, remember two weeks ago when I went to the horse races? Marylou was the name of one of the horses I bet on.'

She is appeased and goes off to work around the house.

Three days later he is once again sitting in his chair reading and she repeats the frying pan swatting. He says, 'What's that for this time?'

She answered, 'Your horse called.'