Sunday Afternoons:  Slack Key Guitar Concerts.  Traditional Hawaiian slack key guitar and `ukulele concerts.  May 5 – Honoring Raymond Kane; May 12 – `Ohana Slack Key; May 19 – Legends of Slack Key; May 26 – From Mountain to Sea.  Tickets: $20 ($15 keiki/seniors).  The concerts are nahenahe - soft and sweet.  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. …