It's not normal what the police did, but these guys really need to start thinking on being useful rather than just demanding "change". I know that they're upset with the whole system (it is unfair), but what Spain needs is hard work, some fresh, young (green) parties stirring up the shallow waters in the parliament, and not random wishes of utopias and system changes. I'm afraid that the times of big, new ideas about entirely new societies are over (thankfully)...
I agree that with the fact that it will hardly lead the politicians to make any change... that it's almost an untopia. But they are not all young, lazy, naïve people: they are mainly (not all!) unemployed people who really tried to get some work and didn't get any (unemployement rate in youth people is dramatic), students who see how their studies will be su much expensive with so less quality next year (a lot of careers disappear, a lot of options have been deleted, teachers will have to do more hours getting less money...) and people who do have a job and a good one (lawyers, doctors...) and are there to help if needed. In my English class there are some young people who explained how they don't know if they will be able to study in the University next year, as they wanted. Because of the extra money they'll have to pay, or because their option disappears or it's included in another one they don't want to study.
The "indigned ones" have not a visible head, and that's a fault that can weaken them, as a lot of wise people says. But they give ideas, not only wishes! They wrote a large list of real changes that government could do to improve (changes for banks, for politics, for economics). I suppose some are impossible to apply, but the majority are well-thought, and should be heard.
Luth, can you give us a hint on what specific things are needed to be done? Do people study things that the economy needs or just party around for 6-7 years (with at least one semester of Erasmus scholarship included which they spend stoned and drunk) to earn a bullshit degree? Because or youth is like this. 
Our studies system has a lot of faults, but there are good students really involved in what they are studing. I suppose the "wooow, 4-5 years of partying around without having to work" kind exists everywhere, here too, but it's not the majority. I know a lot of people who studied hard all the years of their student times, and worked at the same time, in a partial-time job or even a full-time one! Now, with the Bolognia thingy only those whose parents can pay for the studies will be able to study. No student will be able to have any job as they must go to class at the morning and at the afternoon, and work (on their own or in group) the "free time" of weekends or holidays. and they have to make a signature every day they attend class, with very few misses, in order to be able to do the exam. It's not fair: now only young people with wealthy parents, or at least with money enough to pay them the studies, will be able to go University
And... believe me, no one Erasmus scholarship compulsory here. At the contrary... a lot of students want a grant for an Erasmus or getting paid some of their studies and they are not given anything. It depends a lot in what part of Spain you live, as there are other parts of the country (not Catalunya, not Barcelona) where it's easier... and one of the reasons is that Catalans contribute with a lot of money to the central administration but are given back a lot less... but this is really another subject, really.
Sorry, I am usually not a politics person, I always try to see both parts involved, I don't like to randomly complain... but that crisis have increased problems in a way that even a blind would be able to see them
PS. The studies problem (of course, the job problem too) really concerns a lot to me: I was able to study almost with no working of my own, until the last times, but it was cheaper by then. If I had to study now, I suppose my parents could not pay me, and I would not be able to work (both for the impossibility to get any job and for the Bolognia rules). So, I suppose that, if I had been born 10 years later, my future would have been a lot worse. And that future is the one that awaits for our young people. And that's bad
