Buddhism firstly does not believe in the existence of an omnipotent being i.e. God. Instead, there is a concept of, if you will, the universal law. To better understand this, think of laws of physics (like inertia), those things that all physical things abide by, but we simply do not know why.
All beings on this Earth are bound to the 'cycle of suffering'. Suffering does not necessarily mean it must be painful or you must not like it, but it means that they are worldly things. i.e. by being bound to these things, you are 'suffering' as in you are not free and you will not find true peace. If you die, you will be reincarnated to suffer through whatever you deserve depending on your karma in the past life.
Buddhism believes in freeing oneself from the otherwise neverending worldly suffering through detaching oneself from worldly things. Buddhism says you will never cease to feel angry, jealous, happy, or whatever as long as you are attached to worldly things like pleasure, love, and hate. Attachment to physical things also contribute to this suffering cycle. All the things that you see, hear, feel, touch, and taste everyday are all created by your brain, so there is no knowing that they are real and true. Thus, it is fair to say Buddhism is about freeing the mind.
When you meditate, you sit still, close your eyes, and clear your mind. This is so that you are less likely bound by 'outside' things, and you can focus on understanding the facts of life and freeing the mind. Enlightened monks are those who have fully detached themselves from all worldly things and therefore have found true peace. Once they die, they will not reincarnate because they are then free of the cycle of suffering.
On an interesting note, the Jedi concept was adapted from Buddhism. That's why Light Jedi's are taught to control the mind, and Anakin is warned against falling in love. I must add that Buddhism does not say you must not fall in love, but love is just another worldly thing which will cause much suffering like hatred, jealousy, and lust (just look at Anakin for example). The whole concept of 'The Matrix' is based on Buddhism (although not exactly the same), that the world is not real and once you have freed your mind and realized the 'outside' things, you become enlightened (like Neo).
Some may say that monks are torturing themselves by denying themselves the pleasures in life. In truth, monks who truly understand Buddhism do not wish for those things because it is 'outside' to them. To them, a new house is the same as a new pair of shoes, all of which is of no importance.