Today my sister asked me to measure her height so she can calculate her BMI. Being the lazy lout that I am I told her to measure herself. And then I started thinking of ways she could actually measure herself. I am embarassed to admit I could only think of two ways: 1) Let's round out her height to the nearest centimetre (oh yes, metric system! get with it). She should draw a line on the ground and mark of the metres. If she places copies of herself end-to-end -- by marking off her head and then placing her feet there and continuing, etc. -- eventually her head will coincide with an integer metre, allowing her to calculate her height. 2) Run into a pool and record the time her feet enter the water, and when her head passes the surface of the water. Then she measures the height of the ground from the height of the water. Of course she shouldn't jump into the pool, but simply run forward. A simple calculation will give her height. Of course neither of these ideas is practiceable, but could work in theory. Nevertheless it's quite fun to think of ways she could measure her own height. Can you think of any other ways?