Hide your PIN within a phone number.
It's tough to remember all your PIN numbers for bank cards, phone cards, and whatnot. Of course, it's not a good idea to write the PIN on the card itself. And it's not practical to carry small slips of paper with the number written on it everywhere you go. But you can use a simple trick to keep track of all your PIN numbers. Enter fake names in your address book and list what appear to be phone numbers - but are actually PIN numbers - beside it.