There are only three times in my life where I have seen the entire audience react to a movie.
The first was the Teenage Mutant Ninja Turtle movie. I probably saw it opening weekend. There were a ton of kids there, and they cheered through the whole movie. It was a lot of fun.
The second was Aracnophobia. This was billed as "thrill-omedy", except there was no 'omedy' in it. The whole theater screamed through the whole movie. It was pretty scarey. To top it off, my friend two seats over me, kept reaching over and used his hand to 'mimic' a spider crawling up my back.
The third movie was Clerks 2. I have never heard that much laughter in a movie theatre ever. At one point tears were starting to roll down my eyes because I was laughing so hard.
With so many movies, the best parts are put in the trailers and commercials and there are no surprises in the theatre. You may have heard the line "There is only Return, and its' of the Jedi not the King," right? While that is a memorable spot in the movie it surely doesn't tip the iceburg of the humor that lies within. With Clerks 2, the best parts are not TV safe!
If you are easily offended, you might want to back off this one. Experience with Clerks is not needed, but you should see it anyway because it's a fantastic movie.
Oh, and you can get your name in the credits on the DVD. There were about 5 minutes worth of name scrolling in the movie version.