Old reliable timer plug, only better
Belkin WeMo Switch
Price: €50 Rating: HHHH
We're all familiar with timer plugs that allow you to turn a device on or off according to an in-built clock. This takes the concept one step further. The WeMo Switch connects to your home wi-fi so that you can control lights, televisions, heaters or anything else from another room. There's also an accompanying free app (iPhone and Android) that comes with it which does the same thing.
This app is pretty detailed, allowing you to set up different devices and control them whenever you want from wherever you want. The nice thing about it is how easy it is to set up -- it takes about 60 seconds out of the box. The only downside is that it's a little pricey for a plug, even one with this kind of enhanced functionality.