Friday Evenings: Slack Key Guitar Concerts.  Traditional Hawaiian slack key guitar and `ukulele concerts. April 1 – Legends of Slack Key; April 8 – Whales Homecoming; April 15 – Hawai`i’s Sunset Music; April 22 – Spirit of Slack Key; April 29 – Hawai`i’s Cowboy Music.  Free gift drawing.  Tickets: $20 ($15 keiki/seniors).  Slack key guitar and `ukulele in the real old style.  All traditional music with songs and stories of the islands, telling the history of this Hawaiian musical art form. …