Pillow Talk is a project by interaction designer Joanna Montgomery aimed at helping long-distance couples stay connected. It's still in the prototype phase, but she's gotten enough interest that she's already raised investment funds to help make it a reality.
It works like this: each person has a special pillow and a sensor band for their chest. When they go to bed, the other person's pillow will glow softly. When the other person goes to sleep, they'll actually be able to hear their partner's real-time heartbeat through the pillow.
You can find out more about Pillow Talk and check on how the project is coming along at the creator's website.