With calculators on everything from your most basic dumbphone to your computer, there's really no need to get standalone calculators (unless it's the ultra-complicated scientific variety). The Wrongulator, however, gives an entirely different reason for owning one -- it can make for some ridiculous fun.
Designed for pranks, the calculator puts out intentionally wrong results every time out. Sneakily exchange it with the calculator your friend is using to compute his expenses for the month and watch him cry in horror trying to figure it all out. Oh yeah, and laugh while you're doing it.
The Wrongulator is a solar-powered calculator that looks just like the rest of them. Unlike many prank gadgets, this one doesn't give out the joke with a large label, so you can really trick people into thinking that "5 + 5" is supposed to be "49." I mean, the calculator says so!
Given how people rarely look at partial results when punching lists of numbers, we doubt they'll even notice the kind of magic this thing is doing. In fact, if they see a number like "25" in a computation that should result in seven digits, they'll usually just assume they hit a wrong key somewhere and start over. And over. And over.
Word of warning: don't switch this with the calculators the guys in payroll are using. While it can mistakenly result in doubling your monthly pay, it could very well dwindle it down to nothingness. Don't tempt fate. UK gadget shop RED5 has the Wrongulator in stock, priced at £4.95.