His maternal grandfather was one of the original Warner Brothers; his father is producer-director Mervyn (Wizard of Oz) LeRoy; his stepfathers included showman Billy Rose. Thus, from the age of 5, Warner LeRoy wandered around the studio back lots and dreamed. "I always knew I would create," he recalls. But not movies. "I've seen too many people lost in the shadows of older talented relatives." Now, at 39, LeRoy has cast an elephantine shadow of his own. This summer he splashily opened in the middle of New Jersey what is ballyhooed as the "world's largest drive-through safari park outside Africa" in conjunction with the largest entertainment colossus north of Disney World. The whole 1,500-acre, $50 million extravaganza is called Great Adventure. And when the bugs are out (its Ferris wheel got stuck opening day leaving Jersey's U.S. Senator Harrison Williams high and dry for an hour), the park will likely live up to its name.

The so-called theme parks are the current hot number of show business. The more than 35 such complexes in the U.S. grossed $500 million last year and assertedly outdrew professional football, baseball, basketball and hockey combined. Great Adventure is strategically situated to coin money—just 90 minutes from Manhattan and 45 from Philadelphia. It is also just two hours from rival Jungle Habitat, owned, ironically, by Warner Communications, the conglomerate that includes LeRoy's family film studio.

Though close to his family back on the West Coast, Warner LeRoy always aimed to wind up, if not in Jersey, back East. He wanted, he says, "to get involved with the real world, which is not California." After prepping at Switzerland's chichi Le Rosey and Connecticut's Hotchkiss (which he despised), Warner breezed through Stanford, in English, at 19, and headed for Broadway. He was an assistant to writer-director Garson Kanin, acted in a show that ran 12 nights, directed, and produced, among other works, Tennessee Williams' Garden District. He was always an innovative showman, a founder of one of the earliest off-Broadway theaters and one of the first movie-house owners to exhibit classics ("We'd rent Casablanca for $10 a week and gross $20,000").

His breakthrough was the opening, in 1965, of Maxwell's Plum, Manhattan's most stylish swingles restaurant (a Tiffany glass ceiling, Charles de Gaulle's former chef) and currently the biggest volume-per-seat establishment in town. (Warner's personal net is $200,000-plus per annum.) The kitchen is so formidable that nonsingles such as George McGovern and Henry Ford are regulars when in town, and Warner has put on 60 pounds on the job. Among those who discovered the LeRoy flair was Hardwicke Companies Inc., a fast-food company, which bought a half interest in the restaurant and ponied up the millions for Great Adventure.

With his new enterprise, LeRoy now leaves Maxwell's in the care of his British-born second wife Kay, the mother of their 2-year-old daughter Carolyn Plum. What's next? If their Jersey park succeeds (and why shouldn't it, with a shortage of water fountains and the cheapest soft drink 40¢), Hardwicke and LeRoy are contemplating a dozen more Great Adventures.