Check out this Mario-themed doorbell made with a PIC16F628A microcontroller and a dual 7-segment LED display, from hackaday.
Is your doorbell not exciting enough for your guests? [Joe] wanted to provide a little entertainment for his visitors, so he redesigned his doorbell with a Mario theme.
Whenever someone presses the button—which carries the Mario coin image—the segment display increments and the Mario coin sound plays. To add variety, the life-up sound plays at every 10 coins and the mushroom upgrade sound plays upon reaching 100. [Joe] tried putting the life-up sound at its appropriate 100′s place and the mushroom sound at every 10, but he decided the brevity of life-up was more tolerable in the 10′s slot.