Moonwatch by The Emotion Lab...I feel like I should have this.
A wristwatch that tells what phase the moon is in. Designed to establish a relationship between the moon cycle and a person's emotional states, "It's a new concept of time based on nature which invites people to reflect upon and gain a closer understanding of their mood and daily life on earth."
The Moonwatch also shows the time with a push of a button which switches between the two interfaces, time and moon phase. During the day the time is indicated with a black background and during the night the interface changes to white in order to improve visibility.
Found thanks to Mocoloco.