Giovanni Ribisi goes the distance to portray a character--especially if it calls for a sun-drenched stint in Italy.

It's 10 P.M. The hushed hubbub of chatting diners in the chateau Marmont's tranquil courtyard makes the traffic on the Sunset Strip seem very far away. Then Giovanni Ribisi shows up. He's all energy, showing no sign of the wretched insomnia that forced him to cancel our meeting earlier that afternoon. "I didn't sleep for two days," he apologizes. "Literally." He appears rested now, but then again, he's only 26, and his youthful, friendly fist of a face is undeniably appealing, rested or not. Attentive, laughing, and sipping caffe macchiato on the hotel's veranda, he comes across as what used to be called a "nice young man" but these days is called surprising. Ribisi has never run rampant with Young Hollywood, he doesn't make the tabloids, and he's a devoted husband and father. Good son that he is, he's taking his own father, Al, with him tomorrow to Italy, where they plan to search for stray Ribisis after a brief stop at the Giffoni Film Festival.

The sleep-deprived actor has good reason to feel a bit fatigued: He's been working…