Here are the websites to the baking challenges I've found. Feel free to add others!
The Daring Bakers (or Cooks) - www.thedaringkitchen.com
Bread Baker's Apprentice Challenge - http://pinchmysalt.com/the-bba-challenge/
Martha Stewart's Cupcake Club - http://mscclub.blogspot.com/
Tuesdays with Dorie - http://tuesdayswithdorie.wordpress.com/the-rules/
Barefood Bloggers (Barefoot Contessa followers) - http://barefootbloggers.wordpress.com/
Vegan MoFo (Month of Food) - http://veganmofo.wordpress.com/
Craving Ellie in My Belly - http://cravingellieinmybelly.blogspot.com/
Some great blogs...
Madcap Cupcake - http://madcapcupcake.wordpress.com/
Adventures in Food of a Stay at Home Mom - http://adventuresinfoodofastayathomemom.blogspot.com/
The Repressed Pastry Chef - http://therepressedpastrychef.com/
King Arthur Flour Blog - http://blog.kingarthurflour.com/
Cupcake Bakeshop - http://cupcakeblog.com/
The Baking Sisters - http://bakingsisters.blogspot.com/
