National Trails Day: Hike to Makapuu Head for the sunset and the rise of a full moon, 5:30 p.m. Saturday. Pack a picnic. Costs $3. Call the Sierra Club at 538-6616 (box 2) for details. On Sunday, the club also leads a Tripler Ridge hike for $3, and invites participation in trail building for the Maunawili Falls access.
The Hawaiian Trail and Mountain Club offers four hikes, at $2 each. For the six-mile Kaunala hike above Pupukea 8 a.m. Saturday, call Steve Brown at 836-4940; for the six-mile Likeke hike featuring a waterfall, 9 a.m. Saturday, call Dick Davis at 247-3922; for the eight-mile, up and down Manana Ditch hike 8 a.m. Sunday, call Doug Klein at 235-8330; or for the four-mile Wiliwilinui hike up a ridge 9 a.m. Sunday, call Donna Brown at 422-7830.
Manoa Cliffs hike: Naturalist Norbert Larsen leads a three-mile hike through the Tantalus rain forest, Saturday. Costs $5. Call the Hawai'i Nature Center at 955-0100.
Reef walk: Waikiki Aquarium staff talk about reef walking safety, conservation and the natural history of marine life, 7:30 to 10 a.m. Saturday. Costs $8 adults, $7 children. Register by mail. Call 923-9741.
Honolulu Zoo: Enter the nightlife of the zoo's citizens, 7 to 9 p.m. Saturday and Sunday. Admission $7 adults, $5 children. Reserve at 971-7188. Free botanical walk 8 a.m. Wednesday, and admission $2 with the Yum Yum Tree Seniors Card.
Swing Dance Party: 6 to 9 p.m. Sunday, Ala Wai Golf Course Palladium. Admission $4. Call 599-7740.
Folk dancing: The Pleasant Peasant Band plays music for Bulgarian, Greek, Armenian and other international folk music, 7 to 9:15 p.m. Sunday, Makiki District Park. Donation $3. Call 239-7078.
Tai chi at Honolulu Zoo: Practice of Chinese martial art begins 8 a.m. on the first and third Wednesdays of each month. Costs $6 general, $4 kama'aina, $2 with Yum Yum Tree senior card, $1 children, and free for kids 5 and younger. Call 971-7174.
Country-western dancing: Bruce Langley and Philis Johnson teach beginners' two-step and line dancing, 7 to 9 p.m. Thursdays, June 6 through 27, Maunawili Elementary School Cafetorium, Kailua. Admission $2. Call 262-0869 or 262-7441.
Unusual tropical food plants: Workshop focuses on natural growing methods for small farmers and gardeners, 9:30 a.m. to 4:30 p.m. June 15 and 16 in Kona. Includes tour of a developing agroforestry farm. Costs $50 before Saturday; $60 after. Call Kim Wilkinson at 324-4427, Big Island.