The Refrigerator.
Most would just take it as it is, but the way I see it, the machine is much more than meets the eye. It is a magnificent invention that has more potential aside from the obvious.
1. The fridge is a makeshift air-conditioner
Not everyone could afford to install an air-conditioner. I know I can't. But I do have a fridge, and at any moment where I am in want of an air-conditioning, I could just open the fridge and sit in front of the thing for a while.
2. The fridge is the safest place (probably)
If by any chance your town got attacked by an air-raid and there's just no bomb shelter nearby, run for the fridge. Did you watch Indiana Jones? He survived an explosion which destroyed an entire town by, you guessed it, hiding in a fridge.
3. And the fridge's best kept secret...
Think about it. The fridge allows you to bring to the future stuff that, without the presence of the fridge, would've never lasted that long. It's so obvious. The fridge is essentially a time-machine!
And that is just some of the things about the fridge that most people might have never even realized about.
Okay, so maybe I got a little over-excited about finally having a fridge to call my own. First fridge is the coolest, after all =)