I just got back from attending the St. Louis Tionol this weekend and it was a great experience! My only gripe is that I wish I could have taken multiple classes 
For all you harpists (harpers, harperists, harpies, et.al.) if you have an opportunity to attend a workshop with Grainne Hambly-- do whatever you can to be there! She is, simply put, amazing.
In the time we spent with her, she opened up my eyes and gave me a new outlook on playing. I’ve been at a musical plateau for a number of years, most of which comes from my background as a classical musician (or as my whistle and flute teacher likes to say “paper trained”). It was so refreshing to work on playing without music.
My first teacher was a lovely woman, but also came from a classical background. There is a huge difference in learning traditional music in a traditional fashion vs. “paper training”. I wish that I had a teacher close by who was brought up in the traditional style. It makes a huge difference in approach.
The most important thing I came away from this weekend is a new approach in looking at the harp: primarily, it is a melody instrument (like whistle, pipes, fiddle, flute, etc.) and not a piano. My left hand has always been my weakest link, and Grainne showed us how if you focus on the melody-- on the tune itself, you just add a little open fifth drone and then play single notes against the melody (in octaves or thirds or fifths) in the left hand, you have a wonderful, traditional sounding, piece. She has inspired me to work on arranging my own pieces and to not shy away from instrumentals (as I usually hide my playing behind my singing).
I know that Grainne will be at the Somerset Folk Harp Festival (July 29-August 1 in New Jersey). If you are in the area, or can get there, I highly recommend it.