The activities that are available to you will vary depending on where you choose to go on holiday. If you are on a city break, chances are you are going to be spending your days looks at museums, architecture and other points of interest around the city. If you go on a beach holiday, you will have plenty of sandy stretches and lots of sun and sand.
There is a real skill in pleasing everyone with your choice of activities. If you have children, make sure you pick some activities to please them. Stay somewhere with a swimming pool, where they will be able to burn off some energy. You can then do things for adults as well, like visiting museums or going on a day trip to a more remote destination. It will teach your children about the culture and history of the place they visit and they will certainly appreciate that in years to come.