1. Via the Boing Boing Gadgets site: Three researchers at MIT Media Lab have devised a prototype "Bar Of Soap" device (so called for the shape) that anticipates what you want to do with it based on how you hold it. For example, if you hold it like a phone, it becomes a phone. Or if you hold it like a TV remote, that's what it is.
2. Via New Scientist: Reseachers at Glasgow University have developed a functionality called "Shoogle" that uses a phone's existing speaker and vibrator to simulate things like water or balls sloshing or rattling around inside it.
Why‾ The water sound can sound almost full or almost empty, thus indicating how much battery power, for instance. The rattling balls could indicate how many new messages are in your inbox (one ball = one message, two balls = two messages, etc).