How does it relate to Hellenic traditions? Some beginning research:

Philokhoria

http://neokoroi.org/artemis.html

An interesting interview with Thista Minai: http://www.sequentialtart.com/article.php?id=976

Prometheia is a modern day Greek festival that is basically celebrating summer solstice: http://sites.google.com/site/hellenionstemenos/festivals/prometheia

Other thoughts:

Skira: http://sites.google.com/site/hellenionstemenos/festivals/skira

Arrephoria: http://sites.google.com/site/hellenionstemenos/festivals/arrephoria

Dipolieia & Bouphonia: http://sites.google.com/site/hellenionstemenos/festivals/bouphomia—dipolieia