ideas
Some of the things students I've taught loved the best were pretty simple, like a tattoo station. You can get tons of the very cheaply from Oriental Trading. I've taught from K to 7th grade and all of them loved the tattoos. All you need is a couple patient voluteers with wet sponges and massive amounts of cheap temporary tats. Face painting goes over big, too, if you have anyone who can do that. My current school is in a rural area and we have loads of outside space. We were able to rent one of those inflatable jumping things that had a huge slide attached. We are pre-k through fifth grade and all of the kids had a blast with that. The county even sent a guy from the maintaince crew over with a tractor and trailer to give hay-less hayrides around campus. My sisters' kids school has a "Big Splash" day at the end of the year. The kids bring a change of clothes and play water games. Family Fun's website has some cool water game ideas. Good luck!