At our quilt guild we have a Pizza Box Challenge. Those taking part brought in a pizza box with a block pattern and fabric they would like to see in all of the blocks. At each meeting boxes are exchanged and you get to make a block for someone else based on the theme they have chosen. You use a piece of their fabric and some from your own stash to complete their block. It is a lot of fun because so far the blocks I have made I have not done before and when finished I will have a quilt with the work of others. Being a new guild member it is a nice way of getting to know your quilting friends.