This is part of a retro 6502 computer who's primary reason to live is to have a ton of blinking lights that show what is actually happening in the computer. Each address, data, and control line will have an LED, as well as a HEX display of the address and data.

The clock uses an arduino for control and the AD9833 signal generator to create square wave pulses of variable frequencies for the 6502 CPU, from zero to 16 MHz. But most importantly, it also includes the absurdly slow 0.1 Hz and 1 Hz so you can watch the address, data, and control lines fetch instructions and execute them.
http://www.nerdworld.org/Content/JRC-65/JRC-65%20Computer%20Build%20-%20Part%201%20-%20Clock.html