Internet Filtering
Schools filter a range of inappropriate web material for a number of reasons:

Often game sites are blocked because they are perceived to be "bad" for children. Computer games are no more "bad" than are free reading, chess or outdoor games. They are inappropriate things to be playing when other work needs to be done but they are no more deserving of banning than free reading, chess or outdoor games.
Internet filtering is problematic, there are always inappropriate sites that slip through and valuable sites which are banned. It seems that in the order of 20% of inappropriate sites slip through filters and in the order of 20% of benign sites are blocked. It seems that internet filtering is driven by the need for schools to be seen to be doing something rather than by the benefits it gives.
To quote a few sources:
"Filtering is anti-educational in its explicit manifestation because it prevents students from accessing certain materials that they might find important, interesting, and relevant to their learning. Perhaps more important, filtering is anti-educational in its implicit messages about what adults think about education; it promotes a notion of education steeped in the importance of obedience and acquiescence, while compromising opportunities for independent student questioning and discovery. It manifests a distrust for students and in many cases an exaggerated sense of their vulnerability. As a result, filtering operates counter to what students need to learn in school to discern, discriminate, synthesize, and evaluate. How can students learn to be responsible, to make good social and intellectual choices, if those choices are made for them by filtering the information they can and cannot access? It is difficult to teach young people self-control and judgment by denying them access to those things about which they need to exercise judgment."
"Deep knowledge and understanding, creativity, critical thinking, discernment, wisdom, and judgment are not about the accumulation of facts. They are about grasping the relationships between ideas, information, ethics, and culture. When students search the Internet, the sites they go to are not simply destinations; they are steps on the path to further discovery. When one door is closed, entire hallways of further doors may be closed off as well"
Just Give It To Me Straight: A Case Against Filtering the Internet, T. A. Callister, Jr. Whitman College Nicholas C. Burbules University of Illinois"

"four popular filter programs failed to block objectionable Internet content 25% of time"
"In a study Utah public schools and libraries, ... found that the program incorrectly blocked non-objectionable web pages 5% of the time"
"research into over-filtering has found that filters incorrectly block benign material 21% of the time"
"The survey work and filter effectiveness studies I have just cited, lead me to conclude that software filters and Internet content rating systems, at least as they are currently configured, are not the optimal solution for protecting children from harmful Internet material. Filters and Internet rating systems are a seductively simple solution which promise to solve a long standing problem by simply installing a piece of software. It is my contention however that complex social problems can not be reduced to lines of code. Rather, social problems call for social solutions, and in my mind the most effective and contextually sensitive filtering and rating system ever devised is a concerned parent taking the time to surf the Internet with his/her child."  the appendix, Christopher D. Hunter's testimony to the COPA Commission :
"Most of the schools that the committee visited had installed filters, and many libraries had done so as well. However, when asked what benefit filters offered their schools and libraries, teachers and librarians invariably pointed to the political and management benefits--not a single teacher or librarian said that his or her students or patrons were better off with filters in place"

"filter programs meant to block pornographic content on public computers blocked as much as 25% of health-related web sites when the filter was set to its most restrictive setting"
"we believe that ... Employ(ing) Minimal/Zero Filtering System and Use(ing) Comprehensive Curriculum/Educational Materials Dealing with Digital Conduct (e.g., slander, copyright, spamming, flaming, hate groups, pornographic materials) deserves ... highest consideration" is a site devoted to the responsible use of blogs, photosharing, podcasts, web hosting, educational games, instant messaging and other social software in schools. Our students want to be web authors, create content and take part in distributed conversations, not just web consumers. Non scholae sed vitae discimus We learn, not for school, but for life - Seneca, Epistulae We believe that these tools and resources should not be blocked or banned from schools.