Friday Afternoons: Slack Key Guitar Concerts.  Traditional Hawaiian slack key guitar and `ukulele concerts. April 5 – For the Birds; April 12 – `Ohana Slack Key; April 19 – Spirit of Slack Key; April 26 – Legends of Slack Key; April 26 – Legends of Slack Key.  Free gift drawing.  Award winning traditional Hawaiian slack key guitar and ukulele concerts featuring songs and stories telling its history.  Tickets $25 general admission, $20 Ages 13-19 & over 50, keiki under 5…