I often discovered myself asking how tall is this and what are the measurements of this and that. The solution is often simple: I used my steps, my arms, my thumbs and even my GPS to estimate distances. I even sometimes guesstimated some distances.
Mostly I was right. Today I discovered these two nice applications by Androidboy.
With Smart Measure you can estimate the height of objects using the phone's camera.
Simply lay objects to the screen and measure them by sliding a ruler with your finger.
If you check out these two tools, you will see: Even if you do not use them on a daily basis they are fun to use.