Classic Gaming Expo at The Plaza Hotel & Casino sits at one end of "The Fremont Street Experience". I've had more as much fun at the outdoor concerts, drinking beer out of a giant plastic football mug and basking in the neon light show as I have doing anything else in Vegas. Except for the Expo itself, of course
If you want to get a better idea of what's going on around The Plaza, check in here:
http://www.vegasexperience.com/light_sound_shows.htm
And if you haven't seen it before, do check out the video of the light show. Very cool stuff, and you can't miss it when you're out there.