You could buy expensive items and put them in your children's inventory and move them out to their own houses. You could decided on one kid, and move that kid out and take over their lives, leaving the rest of the family with all the wealthy. B)
Some of my favorite things to do is make my own chance occurrences. I have three jars on my desk.... One for kids, one to add money, and one to take away money. When I feel my game needs a push, I draw from one of the jars, whichever I feel like and use the money cheat accordingly. :p
Some are small things. "Teen earns a new makeover." or "Child sim gets surprise toy in mail." And things like, "Won bingo last night. +$200" or "Lost big at the casino, - $5000". :)
I've also just threw it in the story that Dad had a gambling problem and took all their money but 500 or failed to pay taxes and started over at 0. I've completely destroyed their homes, too, and they survived a tornado or hurricane. :s