My son's birthday is October 6 (around your son's), so the weather is usually really nice. We have had his birthday at River Legacy Park several times. They have picnic tables and such and the kids just run around and play. It has built - in free entertainment. There is another park on Green Oaks with a lot more to do for the kids as well - I think it is called Dunlop Park, but I am not sure. It is on Green Oaks between Fielder and Davis. We have been to some really nice ones where people rented bounce houses at their homes, too. They are usually around $100. That has always been really fun for my kids (and usually some of the moms and dads, too!)