Nicholas Wallen’s tick-talk clock takes an interesting look at what constitutes a clock. Built using an Arduino, some stepper motors, and two homemade wheel displays, it constructs a two-phrase message that might have something to do with the current time. If it feels like it. From his website:

tick-talk is a clock that tells time. Given, it isn’t an extraordinarily useful clock. Instead, it’s how a person might tell time if s/he were asked to sit on a shelf or hang on a wall and say the time every few seconds. tick-talk gets lazy and will sometimes try to change the subject. Occasionally, tick-talk draws a blank.