Have you got/are you getting more kids again? You are always so busy!!!
The 6 yo we have loves playig with our 2yo dd and the two of them play families with their dolls, cars (provide plastic containers, tins, wood etc and they turn it into garages/ramps/etc.), cubby houses (use old sheets drapped over furniture). I have found they love using their imagination and like to play lots of make believe games with tea sets and things like that. They also love doing craft, painting, drawing, colouring, playing with playdoh and watching playschool DVDs!!! The park is also a great place to visit so they can all run around and burn off some energy (could be a bit hard if your by yourself tho keeping an eye on that many children!)
Have fun with all the kids!