This is one of latest ECE4760 final projects from Cornell. They have built a large pace clock that can be controlled and programmed with Android phone via bluetooth interface. FYI pace clocks are used in sports activities like swimming workout timing intervals and so on.
Clock is based on AVR Atmega32A microcontroller that communicates to host through RN-52 bluetooth module and drives four seven segment displays made by using custom PCBs and tons of LEDs. LEDs are controlled by TLC5940NT drivers. Device keeps track of time with external clock/calendar PCF8563Pchip. The control part is on android device where commands are send by using nice graphical interface. Ideal stuff for couches who are short on budget.