If you look at my first posts on this blog, you'll see that many of them are my notes on the PD I received at the New York Math Circle Summer Workshop I went to last summer. This summer's workshop proposes to be even better, with a week of study of the Pythagorean Theorem on Bard College's beautiful campus.
The NYMC instructors and Bard Professors that are leading workshops are tremendous mathematicians and experienced teachers and I highly recommend attending.
They have recently extended registration to April 30, which reminded me to let you know about it.
Go here for more information and registration.
There's also an information sheet.
Go and enjoy!