DIY Portable LEGO Kit with Free Printable Activity Cards. I like this for school, older kids can have activity cards to create planets/atoms/molecules/fractions, younger ones can practice fine motor skills.
Theme Boxes for the Science Center - I like the flashlight. Light bulb in unplugged lamp. Plug it in, under supervision, to see if it works. Put beaters on a mixer . Need to look around for other authentic tasks,Especially for higher grade levels!