All of the above suggestions are great. Every time I thought to add one, somebody else had it. I would emphasize the yearbook pictures on nametags with LARGE printed names so you'll recognize 'those old folks'. (You're who?)
We found a local band from the sixties that had started playing again and hired them. Put them at the end of the 2nd night though for the hard core partiers and volume problem. Everyone had a good time dancing. Cheerleaders lead old school cheers. Food in adjoining room buffet style, stand up eating. 2 nights----first just talk session, second, the real party.