The Prefects' bathroom is only accesible for said Prefects. A huge tub takes up most of the spaces, as thousands of faucets provide different kinds of soap. From pink bubbles to white fog-ish foam. It certainly pays off to be a Prefect.
Muggle Studies is considered to be one of the least interesting classes at Hogwarts. However, studying the muggles gives us new insight, not only on their technology, but also on their way of thinking. You might just find more knowledge, not only about muggles, but also about yourself.