Nobody's looked at my portfolio since senior year of college. That's a good thing, since it got water damaged during a move and I had to throw it out.
I had various design and drafting projects from my classes, etc. I had a portfolio page for each show I worked on with the program title page and a couple of cool-looking photos. And my production books. When we did portfolio review every year, each student had a table to display on. Stage managers were always the most boring displays, so you tried to liven it up with a table cloth, candy, etc. By senior year you didn't display drafting from freshman year, so maybe I had a book open to a complicated cueing sequence. Whoo-hoo.
Since college, it's all been emailing my resume around. And references. I've never had someone ask to look at a produciton book before they hire me. And now I don't keep my books...they're kept by the company that did the show, for their archives. So all I have is my resume and references. I try to keep a program from shows, so I can someday make a scrapbook or something. But that's about it.
So, if your class is doing a portfolio presentation, try to make it as interesting as possible. Photos, programs, etc., but also include your book. That's the physical work you produced.
Hope that helps!