For those with a more romantic bent comes a great project from instructables user 'ghostbust555'. Using an Ethernet-enabled Arduino board it determines the distance between the project and another person using an Android phone running a custom app. The project contains a laser-cut acrylic heart illuminated by bright LEDs - which increase their blink rate when the person with the Android phone comes closer.
For complete instructions, Arduino sketch and the Android code head over to the project page here. And we're on twitter and Google+, so follow us for news and product updates as well.
When recreating your own beating distance heart or building a networked Arduino project, consider using our Freetronics EtherTen. Apart from being fully Arduino Uno-compatible, it has onboard Ethernet, microSD socket, full USB connection (no pesky FTDI cables needed) and supports optional Power-over-Ethernet:
