Oahu is a haven for foodies from morning and through the wee hours of the night.  Great late night bites include cheap, convenient and still ultra-tasty Zippy's Restaurants.  This local legend has locations all over the island and most of them are 24-hours.  They are best known for their yummy fried chicken that many residents would say rival KFC and their special Zippy's chili.  It does not taste like regular chili at all.  It has a sweeter, smoother texture than any other chili.  People who are not used to this chili can either be amazed or disappointed by the unique flavor.  Chili spaghetti, Chili burrito, Chili etc...you get the picture, they are known for their chili.  To get the best of both worlds, try a Chili Chicken plate. 

Had a long hard day with the kids and looking for a family-friendly restaurant late at night?  Big City Diner is also a great choice.  Open late, this family restaurant/sports bar has lots of great food at VERY affordable prices.  They have locations at Ward Centers, Kaimuki, Pearlridge and Kailua.  Sample local fare like the loco moco, their famous fried rice, guava ribs or if you are there REALLY late at night after 10:30pm, you can treat yourself to some macadamia nut pancakes.

Local eats and drinks.  Lychee martini?  At Sidestreet Inn, the patrons are local celebrity chefs who love the low-key hangout, the drinks are local with tropical fruit twists and the food is delicious local faves like their famous pork chops, chicken wings, sizzling steaks all served until the wee hours of morning.  Open til midnight every day, it's a great treat for anyone who needs a relaxing end to the day.  Located near Ala Moana Shopping Center.

Need a late night dessert?  Leonard's Bakery on Kapahulu Avenue near Waikiki is open til at least 9pm every night and til 10pm on Friday and Saturday.  Help yourself to delicious malasadas with various fillings like dobash, custard and haupia (coconut cream).  Malasadas are delicious Portuguese donuts (soft and chewy donut minus the hole).  

Another famous bakery, Liliha Bakery located in the sleepy NEIGHBORHOOD (IT IS NOT A TOWN) of Liliha is known for their delicious Coco Puffs (chantilly & dobash combined to create a dessert that is divine).  Open 24 hours a day except on Mondays when it's close, this eatery is a great hidden gem frequented by locals for the baked goods as well as the diner.  Be warned, this bakery is popular and there is VERY limited seating to taste their delicious local menu of great entrees like hamburger steak, stews and inexpensive burgers.