My smallest class--usually two elementary school girls--had one student missing today. Makes a huge difference, so I needed to transform into the flex-teacher: scrap my lesson plan and come up with a few new activities on the spot. One thing we did was write a story together on the whiteboard, me in blue (though from her prompting) and she in green. Not great, but for her age and level quite good (and, yes, there are a few errors but that's ok; grammar/punct. wasn't the main goal).
I often have my students write on the whiteboard as the action usually promotes self-confidence and lends itself to a student-centered classroom.