Prince Mohammed, 37, also started a push to develop entertainment options as a new economic sector beyond oil. Many of the 58 percent of Saudis under 30 say they were starving for entertainment before the changes. Movie theaters opened for the first time in decades, and a series of government-sponsored festivities took over the kingdom. The largest of them is the continuing “Riyadh Season,” a monthslong extravaganza that will culminate in DJ Khaled and Bruno Mars performing at a rave in the desert.