[TechnoChic] creates a sound reactive LED matrix mask.
[Jennifer Townley] creates a kinetic chandelier called Inverta
[Jason Coon] creates a Kraken RGB LED PCB with diffusor.
[Gaetano Licata] creates a musical glove from a microbit.
[Fred Temperton] creates a laser shark LED coaster.
Marc Teyessier creats an anthropomorphic webcam.
[DAKD Jung] creates a ferrofluid speaker.
There's a build log on Hack-a-Day showing details of the build.
[SQFMI] creates an E-Ink clock.
[Jean Simonet] creates RGB LED "smart" dice called Pixels Dice.
The dice know their orientation when they land and can light up accordingly. They can communicate back their position, opening the possibility of novel interfaces, such as speaking which face they landed on, and allowing custom light patterns for different rolls.
[Jean Simonet] has videos on the creation process, including solder, casting and testing the dice.
[Mike Rankin] creates a tiny laser cutter.
Source is available on GitHub.