I thought you meant you wanted to 'Buy' land...

I never have any problems figuring out to do in Spain, and if I had any doubts at all I'd find out which festivals coincided with my trip (although festivals have previously dictated when I go) and make sure I went to one of those. It completely baffles me when people willfully leave out a major fiesta from their itinerary, I just assume that a Spanish festival is so outside most people's experiences they have no idea what they are missing out on.

As you haven't expressed that you're keen to explore an interest such as Art, wine or gastronomy (there are tons of upmarket tours to cater for people who want to explore the wine regions) my suggestion for a trustworthy and reputable company would be
http://www.wexas.com/

If you talk to a company and they don't suggest that you spend a night in some of Spain's Paradores http://www.parador.es/english/ then move on.