Think of them as Sea-Monkeys' more sophisticated cousins. The Ecosphere Pod resembles a crystal ball foretelling a serene future of red shrimp, algae, and microbes. It's an enclosed, self-sustaining system, so you never have to feed the critters; all they need is natural light. Based on a concept developed for NASA, this microworld is made from handblown glass, plus a bit of earth, air, and seawater. $60 to $150, depending on size

Shopping for a fun guy? Consider this mushroom farm from a grassroots company called Back to the Roots. The grow-your-own kit comes with "soil" made of recycled coffee grounds (BTTR is on track to divert 1 million pounds of caffeinated refuse from landfills this year), and the packaging box doubles as the vase. Within 10 days of opening it, you can harvest up to a pound and a half of recipe-ready pearl oyster mushrooms. $20

A teched-up twist on Uncle Milton's 1950s classic is the Ant Farm Revolution. Western Harvester ants eat their way through the cylinder's green goo, tunneling a mazelike space. Thanks to an embedded lens and an LED light, their huge, crawling silhouettes get projected onto the ceiling — for the coolest nightlight ever. If you'd prefer to give a ladybug, roly-poly, or tadpole habitat, no problem — Uncle Milton's got those too. $40 for the ant farm, $6 for 30 live ants (or catch your own for free)

Watch as children morph into lifelong biology enthusiasts: With the Live Butterfly Garden from Insect Lore, they get a netted pop-up habitat and at least three caterpillars. Give the striped larvae the enclosed food, and within three weeks they'll envelop themselves in cocoons and emerge as Painted Lady butterflies. $20

For fashion that grows on you, add a live-moss ring and lichen necklace to your cart. The ring is made from an acorn, a tiny patch of verdant moss, and an adjustable band. To care for it, spritz it with water from time to time and make sure that it, like you, gets a bit of sunlight. The same instructions apply to the necklace, an antique chain whose pendant is a small glass vial filled with living lichen. Five percent of the shop's profits benefits animal charities. 

Green thumbs know that the best dirt is just worm poop. And the fresher the poop, the richer and loamier the earth. So enliven a gardener’s world with a 1,000-count box of live red wiggler composting worms from Uncle Jim's Worm Farm. The squirmy wonders play as nicely in raised beds as they do in a moist compost bin. Just make sure they’re fed a steady diet of kitchen scraps. $18, plus $11 for shipping