Clothespin Math on a clothes hanger! LOVE this. Easy to make, and self explanatory. I'm thinking a wire clothes hanger would work better, so the clothes pins are easy to slide back and forth (almost like an abacus).
Number Line Jumping: Great for teaching counting on, addition and subtraction and greater than/less than. Love the idea of writing numbers on the plates to easily change the type of number line - include percentages & decimals.