According to Jim Recap: Dino-Mite
Cheryl and Dana plan their first night on the town since the baby was born, and that leaves Jim and Ryan in charge of the rest of the kids. If that doesn't add up to a problem waiting to happen, then you haven't been watching this show for long.
Luckily for Jim and Ryan, Cheryl and Dana have gone to a movie, and they also decided to sneak in some mini bottles of alcohol so that they can have a special treat while they are out of the house. This means that not only will they be gone for a couple of hours, but they will be out of it for a little while after that as well.
While the girls are gone, Jim decides that it would be a good idea to take the kids down to the museum. Not that he'd normally go to a museum, mind you, but since Cheryl is working on some sort of volunteer thing, she has the keys, and that means that they can get in for free, which is right in his sweet spot.
After a bit of wrangling, he convinces Ryan that it's a good idea too - even with the baby. Of course, Ryan nearly forgets the baby on the way out of the house, but he remembers quickly enough, so it's not all bad.
Once in the museum, they take a great shot with the baby in the mouth of a dinosaur, but then they want to get a better one, so they position the baby carrier a little better, and as they do, the dinosaur collapses. Sending Andy out to Home Depot for supplies, they set about putting things back together, with the help of Kyle, who despite his other issues, is quite knowledgeable when it comes to dinosaurs.
Just as they get things back together, they set up for the shot that they missed, and they hear something at the entrance - it's Cheryl and Dana, on their way home from the movie. Unfortunately, all the drinking they did means that they can't make it home without a pit stop, so they came into the museum so they can get all the way home. Everyone manages to hide, except for the baby - he's still in the mouth of the dinosaur.
That's when everybody is busted - the moms for drinking, and Jim and Ryan for making a mess, even though they cleaned it up. Just as they get out, the dinosaur comes crashing down again!
