If your kids like hockey the Bobby Orr arena is pretty cool, climbing the look out tower but might to hard for the young ones, great view though, the boat cruise of course, when u come in from the south end there is a really cool ice cream shop just over the tracks and to the right double wide cones, nice bowling alley etc
If u are considering roaming abit as said science north in Sudbury is a blast , used to take our son there he loved it, lots of hands on for the kids, great mini put coarse 3 miles up, the underground tour at the big nickel and the best burgers in Ontario at the Deluxe, they have been there forever, still wrap orders in foil to keep them warm
Lots to do and just a short drive between the Sound and Sudbury