Str82u - 3:22 pm on Apr 9, 2013 (gmt 0)
In an effort to look more detached from reality - I seem to remember visiting and using the REAL G sandbox site back in 2004/2005 when they DID have separate directory that included new sites to see how they did and cull out bad sites before they hit the live directory; a webmaster could see if they were at least in the sandbox to know they would be coming out in the live results soon.
Seriously, hope someone else remembers this (it wasn't an April Fool's gag either). Also, as I remember it, it wasn't public for long and G started to say they moved away from the practice of two seperate directories for that purpose (sandboxing) and soon after the subdomain went 404. The subdomain was something simple like scratch.google or maybe even just sandbox.google