I used to be really into bonsai. Gardening and forestry related stuff for that matter. I had a few trees, but they all eventually died. I started with lots of nursery stock as a simple and inexpensive way to practice. Ficus were, and still are, some of my favorite trees for a simple way to have a faux-bonsai.
If you dont know too much about bonsai, it takes a lot of constant, continuous, consistent work. Bonsai are like having pets, in that they need daily treatment. If theyre neglected, they die. If they are not cared for properly, they die. Its a beautiful creation and dedication, but I decided a long time ago that it wasnt for me, since Im so erratic. Whenever I would go away for a few days and have someone care for my trees, they just didnt get what I had tried to explain to them, and they were improperly watered, and they died.
There are a number of indoor trees that can be kept in a more normal house plant manner, and can be shaped and manipulated into beautiful forms. Ficus, as mentioned by Salty, is one, and rosemary is another great one. But be careful about snipping too much off the rosemary bush Ive had one for a couple of years, and I keep it teetering on the edge because I use it for cooking too much.
I still have a really nice set of Japanese Bonsai pruning tools that I got from New England Bonsai in southern MA. Now that I know more about Japanese metal working, I appreciate them more than I ever did.