Professional Bull Riders may be a niche sport, but its TV ratings are up 20% this year, and its audience over-indexes with Walmart shoppers. So when bulls and riders showed up at Walmart stores in Sioux Falls, S.D., Little Rock, Ark., and Las Vegas earlier this year, they weren't at all out of place, and made enough impact that the league will take its show on the road to 40 more Walmart stores later this year, with plans to hit another 200 next year.