The Adventurer's Club is a must see if you're going to PI...but don't rush it...you can spend an entire evening there and have fun the whole time...
When my wife and I go, we usually get there in time to see the first comedy show of the night at the comedy club, before the line gets too long...then we head over to the AC for most of the rest of the night...
Don't rush it...take your time and enjoy the atmosphere of the place...sit in the main room for a bit and watch the Colonel and the Giant Mask insult everyone...then go into the library when they call everyone in and enjoy the show...the shows are different all night and each one is more enjoyable then the next...
depending on how old your kids are, they may enjoy it all also...
I have 13 yr old twin boys and we bring them everytime we go...they enjoy the comedy club (which puts on a clean show) and they love the AC....on one occasion we had won a bunch of stuffed animals on PI (they have a section with boardwalk type games to win stuffed animals) and the characters in the AC were taking the kids stuffed animals and using them in the show...they still talk about that....
all I can say is that it's definitely a must see...
have fun!!!