Years agon, when I ran MSDOS I used a folder called TEST to put all kinds of things I was working on into. TEST is a fairly boring name, and not very descriptive of what may be in the directory. Also I ended up with multiple directories (TEST1 TEST2) which told me nothing of where I should go next.
When I moved to Linux, I kept /test due to habit and the lack of a better name for quite some time. Finally I then moved to ~/work which described what may be in the directory, but didn't sound all that fun. Mainly the stuff in /work was stuff I was playing with and learning... not really work in my mind, but it was more accurate of a name then ~/play.
I needed something that shouted out that the folder contained fun things I was working on. Then it finally fell into my lap, a Sandbox. A sandbox as a kid is where you had a lot of fun working on sand castles and other things. Both work and fun! Its also a safe area to work in, without spilling over into other things.
So over the past 5-7 months I now have a ~/Sandbox to play in and I am happy there.
Why am I telling you all this? Not sure... But here is the definition of a sandbox taken from Everthing2 that validates all I said above :)
sandbox n.
- (also `sandbox, the') Common term for the R&D department at many software and computer companies (where hackers in commercial environments are likely to be found). Half-derisive, but reflects the truth that research is a form of creative play.