Grow Your Own Bacteria — Well, More of It

If you have kids, you already have ample starter material for this Bacteria Growth Science Kit. And, while growing the icky creatures is fun enough (growing bacteria isn’t bad, either), you can also use the kit to perform experiments, watching how factors such as UV light and antibiotics battle the microorganisms for dominance. Who knows, maybe you’ll even get the kids to warm up to their next ear-infection treatment as a result. OK, that’s a stretch…

$19.99 from ThinkGeek.