Just because you live in an apartment doesn't mean you can't have a garden! Light-weight terrazzo bowls such as this one below make fantastic mini-gardens!
Here I've filled the bowl with a selection of sedum and other succulents; the centerpiece is a lovely Kalanchoe luciae 'Flapjack'. This plant selection is really easy to maintain, is very drought tolerant and only needs a little trimming back to keep it looking good. You could easily fill a similar bowl with small viola or even a selection of different types of miniature ferns. You could even turn it into a 'kitchen garden' by grouping a number of herbs or soft-leaf vegetables together.
One thing to remember when constructing a 'container garden' is to group together plants that have a similar requirement for water and nutrients. Succulents like things fairly dry where as the ferns will like it quite moist and would require frequent 'misting' with water. The same goes for your vegetables and herbs.....rosemary,sage and thyme prefer dryer soil but coriander, basil, parsley and mint like a little extra water. If you plant a combination of the these together in the same bowl then one group is bound to suffer.
Another thing to keep in mind is the weight of the finished garden. That's why the light-weight 'terrazzo' style bowl is ideal. It makes it easy to move your 'garden' around to catch the sun for ease of watering.
So get creative....see what plant combinations you can come up with and enjoy container gardening!