When you're buttering your bread, pastries or whatever, it's kind of a pain when the butter's been sitting in the fridge and turning into a brick. Rather than waiting endlessly for the butter to soften, you can quickly solve the problem with a cheese grater.
All you do is grab your butter brick and grate it over whatever you're going to eat. This process generates a little bit of heat, but mainly the smaller pieces will melt faster and spread better when they hit your warm piece of toast. This is also a fantastic idea for baking.