If you are hosting a large party and your own yard will not suffice then use a local park if you want to have it outdoors or make reservations at a local gymnastics facility that has fun things for kids to do. The later is what we did and it turned out great. We themed the party as Jedi Training and had the kids practice their jedi jumping skills on the trampolines. The facility also had a foam pit for the kids to leap into. We brought home-made lightsabers and had the kids practice bouncing balloons in the air while playing the Star Wars Theme Song in the background (sounded great over the Gymnastics PA system).