This article from Janet Collins is a few years old but still has good info. Be sure to check for up to date information and prices before visiting the mentioned attractions.

In Jurassic Park, it was called Costa Rica. In Raiders of the Lost Ark, it stood in for the lush jungles of South America. The chameleon setting also forms the backdrop for the movies From Here to Eternity and South Pacific, and even the popular TV show lost. But Hawaii is more than simply an exotic filming location. It’s one of the most popular travel destinations for North Americans.

Honolulu is one of the more popular Hawaiian destinations. Honeymooners, second-honeymooners, and other lovers of sun, surf and sand find much to enjoy in this lively city and outlying areas. It’s also a great place to explore the Islands’ art, culture, and history. Several venues around Hawaii offer seniors’ discounts, but they are only available to those who can prove they are residents of the state. That said, some popular museums and galleries do offer senior-friendly pricing. Here’s a sample:

Bishop Museum
1525 Bernice Street, Honolulu Phone: 808.847.3511
Bishop Museum is the largest museum in the state and the premier natural and cultural history institution in the Pacific. It also has one of the largest natural history specimen collections in the world.

The Contemporary Museum
2411 Makiki Heights Drive, Honolulu Phone: 808.526.0232
This is the only museum in the state of Hawaii devoted exclusively to contemporary art. The growing collection includes works in all media spanning 1940 to the present. Among artists represented are Josef Albers, Jim Dine, Jasper Johns, Robert Motherwell, Frank Stella, Masami Teraoka, Andy Warhol, and Tom Wesselman.

Hawaii Maritime Center (part of the Bishop Museum)
Pier 7, Honolulu Harbor, Honolulu
A great place to explore Hawaii’s maritime history. Also home to a rare full-size humpback whale skeleton (one of only five on display in the world).

Hawaii’s Plantation Village
Located in Waipahu This living history museum and botanical village illustrates life on a sugar plantation.

While everybody loves a discount, few things stretch the travel dollars quite like the increasingly rare free admission. Thankfully, the Honolulu region has a number of sights worth seeing at any price – but they just happen to be free. Here’s a sample:

Hawaii Army Museum
Located on the grounds of the Hale Koa Hotel and the Ft. DeRussy Recreation Center in Waikiki

Hawaii State Art Museum
Located on the 2nd floor of the No. 1 Capitol District Building, 250 South Hotel Street, Honolulu
HiSAM has three galleries – the Diamond Head Gallery, the Ewa Gallery, and the Sculpture Gallery.

USS Arizona Memorial
1 Arizona Memorial Place, Honolulu
Remember this is a memorial site, so please dress appropriately. And since it is located on an active military base, be prepared for security searches.