Word roots. I look at the spelling words, and pick a couple to put up and dissect.
I used to do math, but now tend to use the Boogie board for it.
If I know there is going to be a word in dictation or narration that is hard to spell, I might write it up and ask him to look at it before reading.
Spelling rules. I use Spelling Power, and put up the rule for the list we are working on. I flesh it out (SP is brief on rules), and perhaps put up common exceptions.
Chores, so he can check them off.