Peter D.
Yelp
This is a world-class museum, and one of the best things to do while you're in Rochester.
While it is an amazing place to bring your kids, it's not just a children's museum (still worth checking out if you don't have any). It's a place where people of all ages can play, and learn about the history of play.
If you do have kids, you probably already know about it. There are plenty of places for your little monsters to climb and slide and dress up and perform and learn and color and much more. But there's also tons of interesting exhibits like the History of Barbie, with all the dolls going back to its inception (probably a bit more popular since the movie). If you play your cards right, you might see a dad angry at his son for wanting to play with Barbie, and get to witness the fight he has with the kid's mom (public arguments are the pinnacle of people-watching).
There's a life-sized game of (bear) Operation, the original round Monopoly, Reading Adventureland, a helicopter cockpit, a giant hallway with what must be every video game console ever, and a computer where you can just sit and play the Oregon Trail. I just abandoned my family for 15 minutes so I could discover if I still kick ass at hunting (I do). That said, I did ultimately die of dysentery.
Since the best kids' stuff is often pretend parents' stuff, the mini Wegmans grocery store is a giant hit. Our kids love shopping for food, working behind the meat counter, checking out (and ringing up) their choices, and all of the other things. It's the only thing we've done every single time we've come in, and I imagine that won't change next time either.
Check it out.