Aihualama hike: Follow Donna Brown of the Hawaiian Trail & Mountain Club on the Manoa Falls Trail to the waterfall and then to the Nuuanu Valley lookout, 9 a.m. Saturday. Five miles. Costs $2. Call 422-7830.
Box car competition: Drivers test their skills, 9 a.m. to 3 p.m. Saturday and Oct. 19, north end of Paiwa Road, Waikele. Box cars must conform to standards of American Box Car Racing International. Call 947-3393.
Urban Garden Center: The educational center for home gardeners has demonstrations on tree planting and girdling lychee trees at its open house, 9 a.m. to noon Saturday, 962 Second St., Pearl City. Call 453-6050.
Gardening classes: Ho‘omaluhia Botanical Garden has free classes 9:30 to 11:30 a.m. Saturdays in October. How to select, plant and care for a tree, pruning basics, mulching and composting. Bring work clothes and shoes, bug repellent and rain gear. Reserve at 233-7323.
Kulepeamoa Ridge hike: Join Stuart Ball of the Hawaiian Trail & Mountain Club on a steep slope and along a windswept ridge in Niu Valley,
8 a.m. Sunday. Six miles. Costs $2. Call 955-2091.
In-line skating: The Wheel Thing’s course for all ages, 6 to 8 p.m. Monday, Wednesday and Oct. 16 and 23. Costs $90. Call the YWCA at 538-7061.
“Get Rolling, Hawaii” course for ages 16 and older is 6 to 8 p.m. Tuesdays, Oct. 15, 22 and 29. Costs $65. Call 48-SKATE (487-5283).
Skates and protective gear provided for all classes.
Sports Acrobatics Hawaii: Hawaii Highflyers Trampoline Club for adults and kids, 4 and 5 p.m. Mondays and Wednesdays, McCully Recreation Center. Call Karl Vorwerk at 949-3747.
Waikiki Acrobatic Troupe meets 4 p.m. Sundays at the beach across Kapiolani Park Bandstand; free workout at UH Studio Four 8 p.m. Wednesdays. Call Don Heafner at 536-7205.
Learn to swim: Children practice Saturday mornings at Ala Moana Beach; adults, Monday, Wednesday and Thursday evenings. Free. Call the American Red Cross, 734-2101 ext. 123 or 124.
Free hike to Diamond Head: Meet the Clean Air Team at the Honolulu Zoo entrance, 9 a.m. Saturdays. Three miles to the top. Call 948-3299.
Philippine folk dancing: 2:30 to 4:30 p.m. Saturdays, Lanakila Gym. Free. Call 455-9963.
Hash House Harriers: Social runs with Aloha group 3 p.m. Saturdays; call 948-AHHH (948-2444). Or Honolulu group 5:30 p.m. Tuesdays; call 948-HASH (948-4274).
Hawaii Israeli Recreational Dance: Noon to 3 p.m. Sundays, Ala Wai Ballroom. Costs $3.50. Call 623-3603.
Honolulu Marathon Clinic: Free training runs with Jack Scaff and staff, 7:30 a.m. Sundays, Kapiolani Park Bandstand. Call Norm at 247-4957. No meetings on three-day weekends.
Ikebana classes Lillian Koide teaches flower arrangement 9 a.m. to noon Wednesdays at the Japanese Cultural Center. Tuition $30 per month plus supplies. Call 537-5765 evenings.
International folk dancing: Includes Bulgarian, Greek, Rumanian and Israeli dances, 7 to 9:15 p.m. Sundays, Makiki District Park. Donation. Call 923-0362.
Line dancing: 9:30 to 11 a.m. Tuesdays, Waikiki Community Center. Costs $3. Call 923-1802.
Scandinavian dancing: 7 to 9 p.m. Wednesdays, Ala Wai Golf Course Clubhouse. Free. Call 922-0793 or 955-2577.
Pali Twirlers square dance: 7:30 to 9:30 p.m. Thursdays, Yacht Club Terrace. Call 254-2333.
Honolulu Zoo: The zoo opens at 8 a.m. on the first and third Wednesdays of the month. General admission $6; $2 with Yum Yum Tree senior card. First Wednesdays feature a botanical tour at 8:45 a.m. for $2 more. Third Wednesdays, tai chi practice begins 8 a.m. Call 971-7174.
Nature Conservancy hikes: Two guided hikes a month to Honouliuli Preserve, home to more than 45 rare native plants and animals. Donation. Call 537-4508.