Jason Hickman is a very clever man. Not content with modding an old Sony TV into a Space Invaders clock, he then decided that a mere digital time display was not enough. Instead, he decided to have the hours represented by the extra lives, and the minutes by the aliens.
It works via a double-buffered, flicker-free video generated by a propeller chip, but Jason reckons he'll have to drop the double-buffering as it uses up too much chip ram. And if counting little grey men is too much for you, you can also tell the time at a glance, thanks to the last four digits of the high score.