How about a jail? People can pay to have someone arrested. Deputies capture the "criminal" and they can either pay a fine or sit in jail for a designated amount of time.
you could do games like pin the tail on the horse, horseshoe throw, lasso a cow, things like that. You could do line dancing, the kids love that. we did a hoedown last year and decorated th cafetaria like a barn.
"When you stop learning you stop growing."
My nephew's school had a fall festival where they had square dancers come in,they had a cake walk, pumpkin decorating, they had the games as previously mentioned above, they also made those cut outs to put your head in and took pictures. They also had a chili tasting that people brought in and then voted on a winner. They had raffles, and sold baked goods,soda etc and also sold bandanas, and sheriffs badges I think they got from Oriental traders it was a fun night!