Was just about to post the same thing regarding an observation wheel. We maybe don't need a whole amusement park, but something like that would be cool. Some permanent food stalls for mini donuts and beef on a bun, have a year round livestock presence that people can observe/learn about, etc... A small taste of the 10 day event, for those that can't make it here for those specific dates.
The 10 day event will still be a draw due to things like the rodeo and chuck wagons, the coca cola stage shows, the broader midway, other concerts, etc.... and just the general vibe the entire city adopts for it.