A. Bonsai growing
B. Container gardening
C. Simply giving life to that hard seed!
D. Growing fruit from seed just to see what comes out
E. Growing fruits and veggies for bragging rights
("That lettuce came from my own garden, you know!")F. Hydroponics
G. DIY gardening (building homemade greenhouses, hydroponics systems, etc.)
H. Doing the hard stuff just for a challenge (sprouting a dried mango seed, growing cacti in a hydroponics system, growing trees in pure clay [all these can be done!])
I. Other (post this in the rest of your reply)