I went to the Scottsdale Barrett-Jackson in 2005 and it's definitely something that EVERY car enthusiast should see at least once.
The auction tent is closed to the general public, and only people with bidders passes and their guests are allowed in (I thank my dad for picking up a bidders pass so we could go in and watch the auctions for a while each day as well as walk the grounds), but they do sell general admission tickets to the public who just want to go to the grounds and check out all of the cars. Let me tell you, that show will destroy every other car show you ever go to for the rest of your life because there's thousands of cars there and every single one of them are MINT. You'll never see anything like it again.
The coolest thing ever was when we were watching the auction for the highest priced car that the auction had ever seen at that time - it was the 1954 Oldsmobile F-88 GM Concept Cac that went for a massive $3,240,000
. The place was absolutely buzzing over this car all weekend because concept cars from back then were usually destroyed, and for one of these things to be there for sale was unreal. This car had huge influences on the Corvettes that came out a few years later, which makes it a pretty important piece of history.