Mystery Person Contest
Aside from teaching the importance of detail, this
activity has the virtue of requiring no materials, so it can
be done as a fun activity any time you are stuck for something
to do (maybe you got through everything else at lightening speed),
and you want to reinforce the idea that description is important.
It involves individual writing that will be shared with the rest of the class.
You can run the activity as a contest, depending on the dynamic in your class. Some classes love this;
others feel insulted, as if you are bribing them like recalcitrant children.
Either way, it gets them to write and to share
their writing with each other.