Sunday, March 24: Waikiki Aquarium’s 115th Birthday. Festivities include live entertainment by the Iolani Band, a Humuhumunukunukuapua`a hat decorating activity, an invasive algae cleanup effort, and a birthday ceremony with a special cake.  Waikiki Aquarium, 2777 Kalakaua Ave., Honolulu. 9 a.m. to 2 p.m.  Free for the first 115 attendees.  For information visit www.waikikiaquarium.org.