If you want to see some of the activities people want to do when going on holiday have a look at the following webpage. http://www.sundayriver.com/EventsActivities/SummerActivities/index.html
There you will see an activity guide for visitors who go to the four season resort Sunday River in Newry, Maine -The USA-. They go from 'berry picking' to 'whale watching' or 'mining tours'.
Which one is your favourite? Why? Can you practise that activity in Spain? If so, where? Which of those activities would you recommend to a couple with two children aged 12 and 8?