Best practices for keeping a campus computer network from getting brought down by inappropriate use? I work at a California community college that has chronically underinvested in computing and networking. The school has been gradually increasing wifi coverage, which now includes all but a few areas of campus.

As a result, you can walk through the cafeteria or the halls of the natural science building and see one student after another watching TV shows on a laptop. Yes, it's conceivable that they have an educational reason for doing so, e.g., maybe they're watching "I Love Lucy" in order to research a paper on media stereotypes for their women's studies class. But in reality, I think they just want to watch Spongebob for entertainment.

This causes severe problems, because the network was never designed to be a TV conduit for thousands of students. It apparently was one factor leading to the fact that the entire wifi network went down for the first 6 weeks of this semester.

My school's Acceptable Use Policy forbids various uses such as commercial activity, chat, and playing games, but it does not forbid binge-watching "Breaking Bad" over the school's wifi network. I can understand the concern that once the school starts blocking certain web sites, there is a slippery slope leading toward violations of academic freedom. However, it seems farfetched to say that we have to let students access Netflix while logged in to a student account.

Are technological solutions such as bandwidth caps for student accounts a good option? This would seem to sidestep the issue of academic freedom. Spending our way out of the bandwidth deficit does not seem to be an option; not only do we not have the money, but there is every reason to expect that demand would expand to saturate supply.

Can anyone describe best practices for keeping a campus computer network from getting brought down by inappropriate use?  An ideal answer would describe both a successful policy and how it was successfully enforced without infinging academic freedom.
I see this as a resource allocation problem, not an academic freedom problem. Your network just does not have the resources to support many users with high-bandwidth demand (whether the demand is academic in nature or not), and your school does not want to apportion more money to upgrade network resources.

It sounds like you don't really want to prevent a particular use of the network; if you did, it would be in your Acceptable Use Policy. You just want to prevent a user from hogging network capacity, which degrades the experience for everyone else.

Instituting bandwidth caps (or a similar content-agnostic strategy) to prevent excessive resource use by one individual does not violate academic freedom. For example, Amtrak limits use of WiFi on its trains; streaming music, streaming video, and downloading large files are disabled. This is understood to be a reflection of their unwillingness to spend the money that would be required to support high-bandwidth content, not censorship.

If you want to make sure that students still have access to I Love Lucy and other essential academic content, you can offer uncapped network access in specific areas (e.g., in the library). 

Of course, if you plan to implement this, you should announce the change, explain the reason for it, and expect students to be very, very unhappy about it. "Network" is simply one of the resources that students expect from a college; from their point of view, you are failing as a college if you do not provide a reasonable amount of this resource.