The Ocean Adventure park is popular - dolphin, sealion and high-diving shows etc.
There is the JEST camp - former US military jungle survival school, now open to the public. You can learn jungle survival techniques from the local mountain tribesmen. The hills around Subic Bay (on the Bataan side) are some of the best preserved primary rainforest in the world
Treetop Adventure is a raised walkway and zip-wire adventure through the jungle.
Zoobic Safari has mixed reviews. You can interact with animals there, but I've heard mixed reviews of the standard of care for them. Not been myself, so I can't confirm or deny that.
Lots of beaches you can trip to. The main ones; in SBMA and Baloy, aren't spectacular. Some of the beaches/coves further out in the bay are much nicer. There's a good beach at the resort linked with Ocean Adventure. Also, All-Hands beach is good.
It takes an hour or so (taxi/car) or get a bus from Olongapo to Dau and visit Mt Pinatubo; which is nearer to Clark/Angeles. You can hire a guide to help you hike up the volcano. It's a worthwhile daytrip.