http://www.quiltinacup.com/. This large cup comes with instructions for adding your own quilt block, and it's really easy. For this cup, I sewed selvages onto the batting that came with the cup. Then just use a little glue around the snug top, and you're good to go.
This is a great idea for a workshop to do with your quilting buddies because it's so quick and easy, you'll all go home with a finished product! Have fun and send photos!