Here’s a light app feature to close out the week on a light note. A friend of mine recently pointed out this fun Japanese iPhone application, Mihiro Calculator, which is just a simple calculator with with a stimulating twist. When you press the buttons, famous porn actress Mihiro (I’ve never heard of her, but I’m told she’s famous) speaks out the numbers.

She speaks each button press in a number of different voices, normal, sweet, and sad mode — all of which are innocent enough. But if you press the icon in the top left corner, the app switches to another three voices — night, relax, and angry modes. As you might expect, night mode is the sexiest of them all, and I don’t recommend you try it out at your place of work. Unless you work in a porn studio. Then maybe it’s fine.

As off the wall as this app is, it’s a great example of how a normal app can be completely reinvented by adding just a little something special. It’s ad-supported, so ostensibly the developer is making some decent money from it. Mihiro Calculator has been around for quite a while now, but to my knowledge it hasn’t been mentioned outside of the Japanese press. So yeah, you’re welcome!

If you’d like to give all six voices a listen, you can check out the app on iTunes or view our demo video above. Night mode starts at about the 1 minute mark.