On Friday night (Feb 19), I took my kids to the Silver Spurs Rodeo at the Silver Spurs Arena at Osceola Heritage Park. This is a great family event and I do recommend getting there earlier, rather than later. It was a nearly sold out event on Friday.
Cowboy / cowgirl clothing is not required, but if you need to add some to your wardrobe, there are vendors there selling hats, belts and buckles, among other things.