We have generally left Cust Apprec (CA) activities up to our banking centers and they have done things like;
Doughnuts and coffee
Freebies (Keychains, letter openers, etc)
Home made sundaes and floats
Breakfast at the bank (homemade breakfast tacos)
We have many times taken the ideas from the front-line staff - What would they want to do to have some fun?
Hope that helps!
My comments are absolutely no reflection of, nor influenced by, my employer - take them at your own risk.