I think this needs to come back. Now, I don't mean for children, since it's still on their boxes, I mean for adults. If I could do it, I would make every box of "adult" cereal like the kid's cereal. I want mazes on my box and random facts about...whatever. I want to find a hidden treasure in my box of cereal. It doesn't have to be a cheap toy, I understand not everyone is going to jump for joy at finding a top to spin on their desk at work. Still, I want something to brighten up my morning.
It's little things like this that I think would make the world a happier place. I also think a lot could be done with this idea to improve life in various ways. For example, October is National Dental Hygiene month (had to google it), for the month of October all boxes of "adult" cereal have little containers of floss in them. It seems silly, I'm sure, but if that gets even 1 person to floss regularly, then I don't seem the harm in it.
How about a folded up crossword, or word search? Maybe a how-to oragami swan? There are a million things they could put in there that would make my cubical hell slightly better, even for a day. I personally go through a box of cereal every 3-4 days. So two toys a week, just for me sounds pretty badass.