California Pizza Kitchen   When a name is boiled down to its initials, you know it's ingrained in our brains. How many times a month do you say, “Let's meet at CPK”? Perfect for a quick weeknight dinner, a pre- or post-movie meal, or a shopping break, the three mall locations (Kahala, Ala Moana and Pearlridge) are always busy because the service is fast, the food's reliably good and it's reasonably priced. CPK is also family-friendly with many choices the kids like. The menu roams beyond pizza to pasta, salads, soups, sandwiches and rotating specials.   Ala Moana Center: 1450 Ala Moana, fourth floor. 941-7715. Kahala Mall: 4211 Waialae Ave. 737-9446. Pearlridge Center: 487-7741. 11 a.m.-10 p.m. Sundays-Thursdays; 11 a.m.-11 p.m. Fridays-Saturdays. No reservations. AX, DC, DS, JCB, MC, VS. No checks. $$.  Web site: www.cpk.com