Formal definition:
Mindfulness is about being fully aware of whatever is happening in the present moment, without filters or the lens of judgment. It can be brought to any situation. Put simply, mindfulness consists of cultivating awareness of the mind and body and living in the here and now.
...two kinds of mindfulness: formal, (see above!) which involves setting aside some time each day to sit, stand, or lie down and focus on the breath, sounds, senses, emotions, or bodily sensations;
and informal, which means bringing mindfulness to daily activities like EATING, exercising, doing the dishes, or homework with the kids
This is where you reap the greatest rewards!!
http://psychcentral.com/blog/archives/2011/03/09/homer-simpson-and-the-8-attitudes-of-mindfulness/
