Care for another? Duals unusual but not unprecedented for Indy car series historically
The Izod IndyCar Series' running of dual same-day races at Texas Motor Speedway in 2011 would be new for the circuit in its current incarnation, but not unprecedented for major open wheel racing in North America. That said, it's still rare.
USAC contested Twin 125s at Michigan in 1973 and CART did the same in 1979. CART also held 125- and 126-mile duals at Atlanta in 1979 and 1981.