I got another word misuse pet peeve. I heard this on a sports talk show today: "I wanted to root for my alumni." I also remember hearing on another show something to the effect of "He is an alumni of (such and such university)". Since when did "alumni" become the one correct catch-all word when talking about people and the school they attended?

No, you don't root for your alumni, that makes no sense. You're not hoping that anyone who has ever gone to a particular university is having success in whatever endeavor they are currently involved in at the moment. You root for your ALMA MATER. No, a given person is not an alumni of a school, they are an ALUMNUS (singular) of that school.

It's like saying "I am a big fans of the Jazz". It sounds stupid. Now stop it. :)