DD's 2nd b-day is coming up. We're having a cake & ice cream party at our house with some family & close friends. There will be three boy guests, ages 5, 4, & 3. What activities can we do to keep the kids occupied? Last year we had big flipcharts on the floor with crayons & big foam building blocks and we just let them all play together and they did really well, but I have a feeling that we'll need something more than that this year. What can we do that all of them can enjoy?