How to grow sodium chloride crystals at home
My daughter has this as an school assignment, with some implication that it is some sort of a contest, and we managed to grow quite a few of similar quality to the seed crystals on the site in 4 days, which was the original (poorly thought IMO) deadline. 
The trouble is that no one else was able or cared to do it so fast, so the deadline has been slipping for a couple weeks now, with our best crystals going to school and back a few times, getting scratches and broken bits instead of nicely growing undisturbed. 
A bit discouraging. I'm now remembering how frustrating was for me to take school related things too seriously and discover you cared more than your teachers when I was her age.