April 21

American Red Cross Hawaii Chapter, 4155 Diamond Head Road, April 21 and 26, 8:30 a.m.-2:30 p.m., $110. For those with a duty to act (professional rescuers), learn skills needed to respond appropriately to breathing and cardiac emergencies. This course includes two-man CPR method, use of an automated external defibrillator (AED) and bag-valve mask to care for cardiac arrest and breathing emergencies. (1-800-733-2767, redcross.org/take-a-class)

Waialua Public Library, 10 a.m., free. Greywolf presents a lecture on the reality of medieval life, with authentic handcrafted weapons and antiques, period costumes, demonstrations and more. (637-8286)

Mid-Pacific Institute Technology Center, Seminar Room, 2445 Kaala St., 7 a.m.-3 p.m., free. Donate blood to save lives. Appointment recommended. (848-4770, bbh.org)

Paul Mitchell the School Honolulu, 1123 11th Ave., 5-9 p.m., prices start at $10. Paul Mitchell the School supports Kapiolani Children’s Miracle Network and 11 other charities with special rates on hair cuts, massages, manicures and other services. Reservations recommended. (734-7007 ext. 3)

Kahuku Public Library, 5:30 p.m., free. Learn about finances through games, prizes, speakers and evening storytime. (293-8935)

Hoomaluhia Botanical Garden, 45-680 Luluku Road, 10:30-11:30 a.m., free. Storytelling, crafts and nature walk activities. Bring a snack, walking shoes, rain gear and insect repellant. (233-7323)

Jazz Minds Art and Cafe, 1661 Kapiolani Blvd., 9 p.m., $5. (945-0800)

Hard Rock Cafe, 280 Beachwalk, 9-11 p.m., free. Oahu’s premier bluegrass and Americana music band. (955-7383)

Hawaii State Capitol Auditorium, 5:30-8 p.m., free. Screening of the documentary “Kumu Hina.” (629-9864, qwavesjoe@yahoo.com)