I did this too - and kept track of points myself too - so that I could
give a special reward (usually a special project that only their class
could do).
My elementary classes got points for the following:
1 pt - coming in quietly and getting seated quickly for work - all eyes at me.
1 pt - listening to instructions and asking appropriate questions -
good discussion.
1 pt - working quietly and on task
1 pt - cleaning up on time (stopping when told to do so) - all helping
1 pt - lining up to leave - good review of concepts - all hands to self.
I asked review question (closure) as they lined up - gave each table a
question to answer. Tables that got cleaned up first and showed me
they were ready to leave lined up first.
Each class got a slip from me with their points to to give to their
teacher. All of the core teachers were on board.