The please excuse my dear aunt sally is a great learning tool for memorizing order of operations but I think I got a better tool-- Military Rank
Parenthesis: The General
Exponents: The Colonel
Multiplication/Division: The Sergeant
Addition/Subtraction: The Private
A great activity would be for you to have your students draw each soldier and label them Parenthesis: The General, Exponents: The Colonel, Multiplication/Division: The Sergeant and Addition/Subtraction: The Private.
Now take this problem as an example:
(4 + 3) + 2^2 x 6 and ask what is the generals command? What is the Colonels command? What is the Sergeants command? Wha is the Privates order?