As on the other islands, there's plenty of great hiking on Maui. The trails of Haleakala craters are especially noteworthy destinations. Consult these volumes for trail details:
Maui Trails: Walks, Strolls and Treks on the Valley Isle, by Kathy Morey (Wilderness Press, 2003, 3rd ed.).
Hiking Maui: The Valley Isle, by Robert Smith (Hawaiian Outdoor Adventures, 1999, 7th ed.).
Maui Trailblazer: Where to Hike, Snorkel, Paddle, Surf, Drive, by Jerry and Janine Sprout (Diamond Valley Co., 2003).
Day Hikes on Maui, by Robert Stone (Day Hike Books, 2001, 3rd ed.).
Hawaiian Hiking Trails: The Guide for All Islands, by Craig Chisholm and Arnie Lade (Fernglen Press, 1999).
For an unusual island activity, Maui Cave Adventures will take you spelunking in Ka'eleku Caverns near Hana. You can take the short walking tour (for those six years old or older), or get down and dirty on a tour that involves some climbing and crawling (must be at least fifteen years old). 248-7308 www.mauicave.com firstname.lastname@example.org