Why not get a volunteer to wear a cowboy hat and throw wet sponges at them for money or what about face painting, but instead of the kids getting painted, let them loose on you, that would be so much fun for the kids.

Bury some gold nuggets (sweets) and send them on a treasure trail across to prairie and cactus fields, with clues on wanted posters. Charge them 50p to enter?

Jayne