Sierra Club: Help remove the invasive plant miconia from Kalihi Uka, Saturday. Meet 8 a.m. at the Church of the Crossroads. Call 538-6616.
"Indy" car on display: Patrick Racing Marlboro Indy car in original racing condition will be the centerpiece of a new store, Automobilia Hawaii, opening 9 a.m. Saturday at Aloha Tower Marketplace.
Tantalus Ramble: Five miles into a seldom-visited ridge area which features bird's nest ferns and hibiscus trees, with Phil Booth of the Hawaiian Trail and Mountain Club, 9 a.m. Saturday. Costs $2. Call 627-1693.
Photographing nature: Half-hour class and two hours in the field with Steve Kastner, 8 a.m. Saturday, Hawai'i Nature Center. Costs $5. Reserve at 955-0100.
"Transforming the Quality of Life": Tom Grunden discusses and demonstrates the life-enhancing movements of tai chi and chi kung, 4 p.m. Saturday at the Hilton Hawaiian Village. Free. He has workshops 3 to 6 p.m. Sunday at the Hilton Hawaiian Village and Aug. 24 at the Hilton Waikoloa Village, Big Island; costs $49. Call 885-1234 ext. 2829.
Hayseeds Square Dance Club: Dancing, 7:30 to 9:30 p.m. Saturday, Ala Wai Community Park. Costs $3. Call Dan at 521-1191 or Bud at 671-8040.
Beach clean-up: Meet 8 a.m. Sunday at Nanakuli Tracks. Call 483-8383. Sponsored by T & C Surf and McDonald's of Hawaii.
Ka'imimoana open house: See the National Oceanic & Atmospheric Administration's new research vessel, 1 to 4 p.m. Tuesday, Pier 9, Aloha Tower Marketplace. Call 528-5700.
Free line dance lessons: 7 to 8:30 p.m. Tuesdays in August, Ka Elepulu Elementary, Kailua. Call 266-7815 or 235-7747.
Line dancing: Free lessons, 7 p.m. Thursdays in August, Windward Mall. Call 262-7441.
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.