I know on the website it says to wear formal or semi-formal attire for the final dance. What did most men wear last year? just a suit or what? Also, is semi-formal the same as relaxed professional

Semi formal is what you would wear to your school's semi formal. I believe all the guys when I went wore suits.

hey man you can just wear a suit. we all wore either a suit or khakis a button down shirt, tie, and a jacket just like semi formal attire for school

At the Chicago forum we were recquired to wear a suit to the dance but by the end we were mostly down to our t-shirts.

in boston they told the guys it was nice shirt nice pants, but it's kind of an unwritten law that you wear a suit/ sports jacket.