There are many ways to incorporate grey/gray depending on how you were taught, into your Jo,e decor. Understandably, the trend is a grey like kitchen but, here I found some pretty cool alternatives as well--
And, when all else fails, through a slide through your penthouse, the kids definitely won't mind right?!
"Slide" photos courtesy of 2modern.com blog section. Fine furniture sales.
(Photo source links available)