Snip, you probably are very fortunate not to know this one!
The "blue box" refers to something known as "Kraft Dinner", "KD", or "Mac and Cheese". It is a North American tradition among kids, poor starving University students and anyone on a budget.
It is noodles and a powdered cheese that come in a "blue box" and isn't that great tasting but sure does in a pinch!
Okay, my turn.
English style sausages served with a generous serving of potatoes that have been boiled and mixed with some butter and milk until smooth.