Every hacker should build a clock at some point of his/her life. Here is mine. You can grab the firmware in files section (see big_clock.asm).
I want to tell the story. When I was a kid, I was studying piano in Moscow. Each day I have to travel to school via underground trains. Moscow underground railroad system was always thrilling me. It was build with empire architecture style in mind, so it got a lot of stone detailing, mosaic pictures, sculptures. It's a complete piece of art combined with automatics, heavy machinery, trains, signalling, other tech stuff. Pretty impressive. And there should be a big clock. They are installed at the beginning of the platform. They show real time and also a time elapsed since last train passes near the clock.
Why I wanted these clock on a demoscene festival? What is demoscene then? I do not know for sure for now.