I've been practicing Soto Zen for about four years now.
The main practice is zazen, which can be described as a form of meditation. It involves just sitting still, preferably in a stable posture such as the lotus position and paying attention to what is going on without being caught up in thoughts or imagination. It's about facing reality - the reality of life, the reality of ourselves, the reality of phenomena. We have a tendency to try to escape from reality, not just in the obvious ways such movies, drugs and so on, but into the virtual reality of our streams of thought and imagination. The practice of Zazen is too pay attention to what is actually going on right now. When thoughts or images arise we observe them and ourselves as they arise, and we watch them pass without being captured by them. We don't mistake this constructed, virtual world for the real thing.