Here's another application of math and math application. 
from http://www.boingboing.net/
Quote
Quick, when I say iPhoto, you think of what. Apple, right? Difficult as it may be, forget Apple for a second and add the word "measure" as in iPhotoMEASURE. What is it? Well, what if I told you that you could use a digital camera, even a cell-phone camera, along with some software to measure any items you can snap a picture of? The solution is the iPhotoMEASURE application that I just heard about...
from http://www.boingboing.net/