i think polka dots would be very cute! but also hard to come up with ideas.
i thought for a behavior board you could say "get spotted being good" and use colored dot stickers.
then i thought maybe those large circles on your carpet could be bubbles, or spots, or gumballs, not necessarily 'polka dots'. that might give you more leeway.
spots are working in my head...
Welcome to the Best Spot in 3rd Grade (or is that rude to the other 3rd grade teachers?
The Reading Spot
your newsletter could be The Spotlight
alright that's all i've got. hope this was a bit helpful.