Have I mentioned this one before? My guild is doing it's block of the month challenge in 2013 and this year, we're doing paper-pieced blocks chosen from Carol Doak's 300 Paper-Pieced Blocks. Each month, one of our leaders (Kate) chooses a block and we all do it in whatever fabrics, size, or quantity we want. We keep these blocks for ourselves--no exchanges involved.
My challenge to myself is to work completely from scraps. I'm doing four 4" blocks each month. No idea what I'll do with them yet but I'm having a blast!