BankWest has this “Kid’s Saver Account” which gives you 10% interest, for the months when you deposit minimum $25 maximum $250 without making any withdrawal.

• Available to under-15.
• 10% bonus interest paid on months if you make regular deposit of $25-$250 and no withdrawal.
• No account fee.
• Must link to BankWest’s children saving account.

Quite a few restrictions, but 10% is certainly one of the highest I’ve seen. Time to start saving for the kids.