This number is from the City and County of Honolulu (fire department, police department, Honolulu zoo, etc.).  This is a trunk number, so no matter which C&C office calls you, it will show up as 808-768-0000 and you cannot call back this number.

Most city numbers go through this one. Mine was for an interview with a city office. Its a phone tree root so that people can't call up specific people and bug them

I got a call from this number but they never left a message on my voicemail? who is this?