Generalitat de Catalunya is one key actor in the spanish open data scene. They started to open their data a couple of years ago, and they are doing a great job by offering a high amount of datasets in different open data standard files. You can use the service Gencat Dades Obertes to download and play with data of Catalunya.
These are some iterations that I did for a little experiment regarding childrens names born in Catalunya from 1997 to 2010.
And the process that I followed