All too simple, but damn if I don't like it! Take a humble calculator, and redesign it to suit single-handed use. It ends up looking a lot like a mobile phone. Sure, your mobile can do calculator stuff (if it can't, yours sucks), but having a handy calculator around the house is always a good idea, right?
Available in white, black, yellow, or pink.
Fine. Don't buy one. I don't care. I like it.