I've participated in every year in some form or another (and I was the overall grand prize winner of Season 2). Some of my favorite quilts that I've made were Project Quilting challenges.
The schedule for when the challenges start is:
- Challenge 1: January 3
- Challenge 2: January 17
- Challenge 3: January 31
- Challenge 4: February 14
- Challenge 5: February 28
- Challenge 6: March 14
Each challenge is posted at noon CDT and due exactly one week later at noon CDT.
Here's a post with some tips about how to participate.
The challenge will be posted on the "Persimon Dreams" Project Quilting blog and you can also find links about past seasons there.