Every parent (no, every person) should own a copy of Beautiful OOPS by Barney Saltzberg.
Today, I had a "beautiful oops" of my own. After naps, I was planning to break out our new glitter glue to decorate construction paper flowers, but my flowers looked a lot more like...bugs. (sigh) The kiddos turned my mistake into something beautiful though and decided to add eyes, feather wings, and antennae to one.
They created a whole colony of colorful alien bugs. Tada!