I find that places like museums are the best place to go. Not only do they have kids activities, they also have exhibits which can educate kids in a manner which is not "school like". (if that makes sense)
There are quite a lot of great places to take the kids during the holidays, one idea is taking them to Kings Park. Some other ideas are Scitech, the zoo and Caversham Wildlife Park. These places are always going to keep the kids busy.