I got it by writing a simple login spoofer in Turbo Pascal. The funny thing is I never bothered to remove it and after I graduated, I heard from the actual administrator that they were having a strange problem where the first login of the day spit out a disk full error.
Ha, I did the exact same thing, in turbo pascal as well!
Man, I miss those simple computer systems. I used to go to other peoples' desks and type the word "end" in column 100 of the first line of their program. They'd go mad with frustration trying to figure out why their program always ran instantly, with zero errors and zero output. Or I'd like them watch me type in my 6-digit numeric password, but they still couldn't log in as me because I was slyly holding down the alt key as I typed, so the password was really a single extended ascii character...
Getting up to all those hijinks gave me a love of computers that really set the direction my life would take.