Overnight with the Sharks: Shark researchers Jerry Crow, Chris Lowe and Brad Wetherbee talk about shark form and function then invite you to make your own shark model, Aug. 23 and 24 at the Waikiki Aquarium. Costs $16 general. Call 923-9741.
Diamond Head hike: John Cummings shares the history of this landmark, Aug. 24. Costs $5. Call the Hawai'i Nature Center at 955-0100.
Emporio Armani Hawaii Beach Volleyball: Men's and women's teams compete in a double-elimination tournament, 9 a.m. to 5 p.m. Aug. 24 and 25, Queen's Surf Beach. Free admission. The Boys and Girls Club of Honolulu will receive $1,000 from Emporio Armani and the proceeds from refreshments sold.
Box Car Skill Driving Competition: 9 a.m. to 3 p.m. Aug. 24, Koko Head District Park's upper lot. Cars must conform to American Box Car Racing International specs. Call 947-3393.
T & C Surf's skateboard contest: Top amateur skaters compete on a custom-built street course, 10 a.m. Aug. 24, Aala Park. Call 483-8383.
Manoa Library: Thirtieth anniversary celebration begins with a lion dance, 10:30 a.m. Aug. 24. Carol Welhouse produces animal balloons at 11 a.m.; craft program at 1 p.m.; and "The Magic of Merlinski" by Dennis Dobies at 2 p.m. Call 988-6655.
Taro Patch Party: Get muddy while learning about taro's role in Hawaiian culture and taro farming, 1:30 to 3:30 p.m. Aug. 24, Hawai'i Nature Center. Costs $5. Reserve at 955-0100.
"Run What You Brung" contest: Rising Sun Hobbies offers cash prizes for the best models of aircraft, ships, trucks, autos and armor and dioramas, Sept. 21. Customers will decide the "Best in Show" prize of $500; grand prize is $250; and each category will have first-, second- and third-place prizes.
Kits must have been purchased on or after July 25; receipt must be turned in with entry form. For rules and entry form, see Rising Sun, 835 Keeaumoku St., Suite 201. Call 942-2851.
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.