A “Wizard of Oz” mural loomed over a D.C. park for 23 years. When other artists painted over it, one of the creators — a prominent street art curator — did something surprising: He sued.

Connections of Yellow Car had a nervous wait to earn jockey Nick Slatter the biggest win of his career in the Pertemps Network River Don Novices’ Hurdle at Doncaster. The 10-1 shot faced a 20 ...