Bounce House

If you have extra money and want something fun for the kids (or childish adults) then a Bounce House might be an idea. Besides you can often find them in the shape of a castle. It requires a lot of space and someone to make sure that the kids play nicely, and possibly a sunny sky, but still this might be a good way to keep the children entertained while the adults do all that boring stuff like talking and drinking coffee. :)