ok for daytime activities...
you can hit up DiamondHead...
if you wanna hit a beach you have Waikiki Beach (rent jetskis or just stroll the beach) you can also go to Northshore which is more of a surfers beach because it has a bugger waves...
ummmmm you can take a trip over to the Pearl Harbor memorial which is about 15 minutes from Waikiki...
you can just stroll shop around the downtown area... oh dont go to the Zoo it is dopehead central (just a warning)
as for night life
Waikiki is nothing but a party... clubs/bars all up and down the strip
one that I used to frequent is Moose McGillycuddy's Pub & Cafe its on Lewers (just ask for Mooses and they will point you in the right direction..) its a restuarant but at 7 it turns into a pub/club, they remove some tables to make it room and the drinks flow and it fills with all flavors of women so you can have your selection... they dont close until 4 am so its an all night party...
a few other spots are Zanzabar dance club (hip hop, pop, techno)...
Next Door.. its on Hotel Street which is right off the main strip...
Rumours (is kool dont know how old you are but that is more of the older crowd and music) there are a few strip clubs in the area...
if I can think of a few other spots out there I will come back with details...