Without trees to generate oxygen, humans would have to retrieve it from scuba tanks and the minty breath of local supermen. Keep the air alive with today's Groupon: for $50, you get a garden-steward membership to the Mounts Botanical Garden (a $100 value).

Mounts Botanical Garden’s visitors wander through 14 acres of effulgent gardens blossoming with tropical and subtropical plants from around the world. Exotic trees, tropical fruits, palms, and native Floridian species teasingly tickle the backs of guests’ necks as they meander down the garden's outdoor paths. Good for two adults and two children under the age of 18, Garden Steward memberships confer benefits that include free admission to the gardens, the spring and fall plant sales, and the October 16 fall family festival. Members also receive two free tickets to the connoisseurs garden tour and free reciprocal admission to more than 180 gardens nationwide. Additional perks, such as a 10% discount at the garden shop and special recognition in the member magazine, make members feel as special as a queen beekeeper.