Plug Mug
Plug Mug£9.99 from Gadgetshop
This is a mug with a plug. By unplugging the mug and taking the plug with you, you can put your mind at ease knowing that no one else can use your precious mug. While I enjoy the craftiness of the concept, I'm a little disappointed that the mug is not particularly attractive or especially desirable. It's a fun product regardless.