Mindfulness meditation is defined by Jon Kabat-Zinn as "paying attention on purpose in the present moment non judgmentally."  We take the time and space to feel our breath or body, and notice what is really going on right here right now.  It is a simple practice, connecting us with what is going on in the present moment so that we can work with it and respond more appropriately in our bodies, minds, & lives. 
     Below is a 5 minute video of Jon Kabat-Zinn talking about "What is Mindfulness."