Sometimes, you just need a little more motivation to save money than a normal piggy bank provides. That's what the new Tomy BankQuest bank does; whenever you put in money, it counts it as gold for the little RPG game embedded within, allowing you to go buy more swords and armor and such.
How genius is this? Give it to a nerdy, RPG-loving kid and he'll have to save up real money to buy the weapons necessary to slay the next boss. Sorry kid, no amount of level grinding will let you make the gold you so desperately need. Better go get a real job. Brilliant, and I kind of want one.