Cereal Box Magnet Mover- cut a rectangle of cardboard from a cereal box, outline and cut out a figure on the crease of one of the side pieces and attach a paperclip (see source), draw a maze on the rectangle piece, and use a refrigerator magnet underneath. So simple!
water play with multiple activities. It would be neat to have an area where several short hoses and sprayers with containers could be attached. I'd make it longer so that children would be spaced farther apart but I like the natural look of what appears to be a wooden wall and possible wooden steps or a bench behind it to provide better access from the top.
Alphabet play dough mats. Easy for beginning kindergarten because the letters on mat look like real play dough "snakes".