Target mode?

There is a VERY simple way to access the internal drive of you mac without using a screwdriver: when you startup your mac, keep the "T" key pressed until the yellow firewire (jumping) logo appears. At that moment you can use a firewire cable (unless you own a macbook air) to connect your computer to another one that has firewire: then your original mac will appear as an extenal disk. Warning, all files will be accessible and writable at this stage; if you needed some more protection google for "open firmware set password".

Some place safe.

You've sometimes needed a safe place to store some sensible information, could it be for work's purpouse or for some swiss bank account's password, isn't it ? There is a simple way to do it with some standard tools provided by MacOSX: "Disk utility". Fire it up and then choose "new image" than choose your (maximum) size, choose partition disk type, sparse disk image format and encryption enbled. This will create a password-protected usb-stick like drive when you double click on the "youdisk.sparseimage" file you just had created. (note: disk file will only occupy the space according to the files inside and not the maximum defined sparseimage size).