Sunday Afternoons: Slack Key Guitar Concerts. Traditional Hawaiian slack key guitar and `ukulele concerts. February 1 – `Ohana Slack Key; February 8 – Heart of Slack Key; February 15 – Spirit of Slack Key; February 22 – 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.…