Saturday Evenings:  Kapa`a Slack Key Saturdays.  Traditional Hawaiian slack key guitar and `ukulele concerts.  August 3 – Sea Turtle Serenade; August 10 – `Ohana Slack Key; August 17 – Legends of Slack Key; August 24 – Mountain to Sea Slack Key; August 31 – Circle of Life.  Tickets: $20 ($15 keiki/seniors).  A portion of the proceeds supports Na Keiki `O ka `Aina. Located in the Children of the Land Cultural Center, Kaua`i Village (Safeway/Longs) Center, Kapa`a.  5 to 7 p.m. …