The show really is your best bet to be able to play vintage arcade games in public. The last several years have featured over 400 games each year. I don't know of any other place with that many arcade games spanning the years available for play.
As far as what kinds of games show up, a few games from before WWII show up, and there are occasionally world premier new games. Of course there are a lot from the years in between, with a pretty hefty concentration in the "golden years" of video games (early 80's). Pinballs make up a bit less than half of the total, and video games number over 200, with a healthy smattering of "other" kinds of games (mechanical boxing, gun games, bowlers, "skill" games, etc.).
Most of the super popular games show up (Ms. Pac, Robotron, Medieval Madness, etc.) as well as a bunch of prototype and unreleased games (Marble Man, Big Bang Bar, Kingpin, etc.) You can count on finding something new to you - I always enjoy watching people discover how fun a game they didn't know about is! Seeing younger people discover the fun of an EM like Sing Along, an older video game like Rebound, or an oddity like Ringer really makes the show a success to me. It's also great to see an older "strictly pinball" type enjoying a newer video game like Rush 2049 TE or Point Blank. The best discoveries of all have been kids and parents playing something they would never find anywhere else - and having a great time together - or watching someone who got
dragged along invited by an insistent spouse or friend finding out about Cosmo Gang, Warlords, or Prop Cycle. I think people mostly come for nostalgia and friendship, but discovering something they would not otherwise see is a great bonus. Even a serious gamer may stumble across a game they overlooked in the past and add a title like Mad Planets or Pooyan to their personal wanted list.