Also known as power point and as GPO. Or stopcontact or Steckdose :).
For our friends outside Europe: this is the most common GPO in Europe. Two pins, for + and - each. And the two metal things at the side are for earthing. Plus can be left or right. Round plugs with earthing and the new small plugs with only two pins (like on shavers) can fit in all of them, they all allow up to 16A and 230V. The plugs have no fuse.
Why do I show this? For my birthday I got an electric torch as present. It can be charged with an USB cable. It also has a little charging station where one can hang the torch to charge when not in use.
I think having the torch handy when I go out of the house is, erh, handy, so I bought a new socket outlet, now with USB. After installing the socket and the charging station next to the entrance, I will always be able to leave the house with a fully charged torch battery.