Moonsand
By 999frights onMy wife did not want to buy the Moonsand, but it was Black Friday and it was cheap, so I bought it.My kids really wanted it and were excited to get it.Once they pulled it out to play, I was excited too - over the MESS!
We decided to let them play with it inside, in the kitchen.BIG MISTAKE!They had sand everywhere and I wasn't about to clean it up and neither was my wife.The kids had a lot of fun playing with it, not so much cleaning it up.The sand molds together okay.It will not dry out.We had them put what was left after the cleanup in a plastic zip bag.
The good thing about the moonsand is that even though it was all over their clothes, it was easy to wipe off them.I just took them outside and used my hand to get the sand off.
The kids can keep playing with this, but only outside.

I have heard good things about this, but it must be messier than what I heard.
My kids want this, but thanks for the warning!
Sand belongs outside... Somehow, your wife knew it from the start. ;)