If you think you'll never have a garden—maybe you don't have even an inch of outdoor space, or the tiniest inkling of how to care for plants—I have one word of advice. Succulents.
Get a bunch of the little ones. Arrange them in a container on a tabletop—yes, right there, in the middle of the room—and back away. Instant garden.
Above: Succulents are extremely low-maintenance plants that retain water. All that moisture they're hoarding is what makes them look so plump. You can ignore them for long periods of time without offending them. You can even root them, in a little sandy soil, in a crevice of a branch (as Above). Image via Flora Grubb.
Above: They thrive in extreme climates, such as deserts or the tropics, so succulents are not going to blanch at a little neglect at your house. A set of three potted Succulents is $22 to $31.50, depending on size, at West Elm.
Above: An undrained container can be planted with succulents if you water very carefully. For a similar look, start with a Deep Oval Bowl; it's $24.99 at Bed, Bath and Beyond. Put a layer of pebbles or Tan Gravel (a jar is $8 at Terrain) in the bottom to aid drainage. Image via Flora Grubb.