Many small appliances can benefit from an off-device mains switch, and these are often put on the power cable, or – more rarely – on the wall outlet. But in a trip to Germany I witnessed a nice twist on this theme: putting the switch right on the 220V mains plug at the end of the cable. This was done without in any way increasing the size of the standard plug; and of course it means you could retrofit such switches to any device by replacing a plug, a simpler operation than replacing a wall outlet or messing with the cable in between the device and the plug. Nice product!

Switched 220V mains plug