We will be in Maui from Aug 24-31, with 2 days at the Westin Maui and 5 days at the Westin Maui Villas. On Aug 25 (Monday), we want to spend most of the day relaxing at the Westin using the pools and beach and snorkeling at Black Rock, but we would like to do something for maybe 3 hours that's within a 1/2 hour drive of the resort. We want an activity, not something food or shopping related. Can anyone suggest something we can do on our own that wouldn't cost too much. Other days we will be doing Ziplining, Haleakala National Park, Road to Hana, and the Maui Ocean Center, so none of these please. Maybe something involving waterfalls or special beaches or a nice attraction which isn't too expensive. Thanks!