I'd never even heard of the Pinball Hall of Fame - but found it on a website about free or cheap things to do in Vegas.
If you like pinball you should visit. If you LOVE pinball, OMG - why haven't you gone yet???
Most arcade you'll get maybe 3 pinball games - of if you're lucky maybe a few more. This place has roughly 100 games! Old vintage, mechanical games up to the latest and greatest. I got to play a few old favorites and a bunch of games I'd never seen.
Check them out next time you're in Vegas.
http://www.pinballmuseum.org/