Clap on, clap off, it's a wood cube, it's a clock.  LED will respond to any sound and activate the display.  It even comes with an alarm feature! Available in dark and light wood veneer.
Wood veneer with Red LED digital time.
Clap your hands to make RED LED time appear.
Takes 2 AAA batteries (not included)

L 2.375 x W 2.375 x H 2.375"