You spoil fathers in the same way as you spoil other people:
by making them the center of attention for a day and surprising
them with things that are unusual and that they like. This can be
a bike tour, a hike, a visit to a football match or - why not -
breakfast in bed. But you could also have a barbecue or cook together.
After all, why should fathers be served when it's clearly more fun together?
Pictures that remind us of shared experiences are also very much appreciated.
Basically, it doesn't matter. Just take time for your father and make it a nice day.