We made gum ball machines with 100 dabs. 
We counted 100 drops of water.
We found numbers on the number grid that turned into a mystery picture.
We played a dice game - "Race to 100"
We made a special 100's day snack and counted out 10 of each item to make 100.
We made a cube tower 100 cubes long and saw whether we were shorter or taller.
We made an awesome crown with 100 stickers.
We had a great day!!!