I also follow the 5 minute rule plan - works well for me. In my 100+
enrollments, they take the iRAT until 10 are done then I do five minutes. I
have students raise their hand (or something) while i stand at the board and
add a tally until I hit 10 then I announce.
As for something to DO, I have added brain teasers and whatnot to the back
of the RAT sheet to give them something to do. Sometimes they are puzzles
(like sudoku) or a task like "draw a picture of your plan for spring break."
I don't grade these but many students do them and have fun. It burns the few
minutes so they don't "sit and stare."
For teams, I've given them maps when they finish before other teams and ask
to see how many states/nations they can label as a team. Usually tell them
that any member can't put down more that X labels at a time.
Those are both optional ways for them to engage in something. By
mid-semester teams usually don't have a problem waiting - they chat. I also
let them start appeals once they finish up/before the mini lecture. If they
figure they are wrong they don't turn it in but if they do have a point to
make it gets them thinking about the material they want to ask questions
about or contest.
Erica