If you're into pinball machines, old and new, this is your place. Hundreds of machines of almost every genre--the old "newly electrified" games of the late 40s, solid-state games of the 70s and 80s, shooting games, all the way to digital machines--all working and lovingly maintained under one roof. Take your quarters or small bills, and enjoy an afternoon here. I liked that the machines take their original amount, so most machines are still just a quarter.
There are also drink and candy machines (not just a quarter) in the building. If you're staying at one of the casino resorts along the Strip, it is easy to get there by cab--maybe $10 or so, each way. If you're willing to navigate the transit system, it's a pleasant couple of buses to get there.