You normally just sneak in? Have one of your friends open the side door, or do you pay for another movie then sneak into that one when it's over?
Realistically though, I saw the 1st one in theaters, but I was really young (high school?) so I loved the idea of racing cars. Plus, everyone wanted a Supra back then, so he had a badass one that was faster than a Ferrari.
The 2nd was complete horseshit, but they made them much better from the 3rd on. They made the characters more unique. Not clowns of themselves. The plots got more in depth. The action was better, and (4 on) the final sequences were awesome. I've enjoyed a lot of these. They just aren't realistic at all, but that isn't what I go to see. Seriously, how awesome were those little f1 style "ramp" cars from the last movie? I dug the shit out of those.