ELI5: Explain Like I'm 5
Examples: event driven architecture, why do boats float, double slit experiment, what's the origin of life?, doomsday clock

Blue-plate special

The blue-plate special is like a special meal that a restaurant offers on a special plate that is colored blue. This meal is usually offered during lunchtime and it has a special price that is lower compared to the regular menu price. The reason why the plate is blue is because it is a color that attracts attention and it makes the meal seem more special. It is a great option for people who want a tasty and affordable meal during lunchtime.