In large bowl, soak rice stick noodles, if using, in enough hot water to cover, for 20 minutes; drain. With kitchen shears, cut noodles into 4-inch lengths. If using angel hair pasta, break in half, cook in large saucepot as label directs, then drain and rinse with cold running water.
Meanwhile, in small bowl, combine lime juice, fish sauce, and sugar. Prepare all remaining ingredients and place next to stove for easy assembly.
In 12-inch skillet, heat oil over high heat until hot but not smoking. Add shrimp, garlic, and crushed red pepper; cook, stirring, 1 minute. Add eggs and cook, stirring, until just set, about 20 seconds. Add drained noodles and cook, stirring, 2 minutes. Add fish-sauce mixture, half of bean sprouts, half of peanuts, and half of green onions; cook, stirring, 1 minute.
Transfer Pad Thai to warm platter or serving bowl. Top with remaining bean sprouts and sprinkle with remaining peanuts, remaining green onions, and cilantro. Serve with lime wedges.
Tips and Techniques: On the side: Serve each person 1/2 cup steamed spinach. Start with 3 cups raw spinach leaves per person and steam or microwave until wilted; toss with a few drops of soy sauce and 1/2 teaspoon grated peeled fresh ginger, if desired.