Keep your passwords handy

Yesterday was the first day of classes. In the two that I held, a total of maybe a dozen students had to run down to the computing center to find out what their system passwords are, so they could do the in-class activities. How do you keep track of all your different passwords? I have a dozen or more, and of course they change from time to time. It isn't easy. The people who run our computer center will tell you not to write them down. But I do, though I'm not as bad as the guy in the cartoon who has post-it notes all over his desktop showing his secret passwords. Do you have a better way of keeping track of them?