Sam Hornish Jr. is leaving the IndyCar Series for a full-time ride in NASCAR, joining the mass exodus of open-wheel stars fleeing to America's most popular racing series. The three-time IndyCar champion told The Associated Press he will drive the No. 77 Dodge next season for Penske Racing with Mobil 1 as the sponsor. "I feel like this is something that is a new and unique challenge for me," Hornish said Thursday.