I want to give credit where credit is due. This is a post by a blogger that I read sometimes. I cut and pasted this from his blog (I wanted to include the graphic), and you can go read some more of his blog by clicking here. (I think I found him because of our friend, Jake T. )
The Sweet Spot (AKA, The Tangible Kingdom)

Community Groups are the heart of who we are and what we do at Church of the Cross. We gather on Sunday mornings to worship, to be refreshed, reminded, edified, built up and then we scatter throughout the week to live in community on mission. We have said it before, but, even though on paper we only “do” two things: Sunday morning Gathered Worship and Community Groups, we actually ask much more of you than some churches who might fill your schedule with something every day of the week. We ask our family members to re0rient their entire lives around the Gospel; to begin living everyday life with gospel intentionality and Community Groups are the primary context for this to happen.
The Community Groups are made up of three spheres, “Communion,” “Community” and “Mission.” We first say this diagram in Hugh Halter and Matt Smay’s book The Tangible Kingdom, and it made a lot of sense to us. Halter and Smay define “communion” as our connection with God; worship, both personal and corporate. Community is life together and mission is being focused outward, on others. Our Community Groups aim to be the intersection of all three, the “sweet spot.” It is when all three of these spheres intersect, that Halter and Smay say the kingdom becomes “tangible” for people.
Many Christians groups seem to do well in two of the three, but, neglect any third sphere and you have something entirely different. For example, neglect “communion” leaving “mission and “community, and you have a social-service project. You might be doing “good,” but it is not Gopsel-good. Leave out “mission” for “communion” and “community” and you might have a good worship service. Forget “community” from “mission” and “community” and you might have a short-term missions trip, but you don’t hit the sweet spot, it’s not everyday life with Gospel intentionality.
Community Groups are meant to be a context in which we can aim for the intersection of each sphere, where communion, community and mission so inform our lives that the kingdom becomes tangible. This means that they are not just small-group bible studies. They are that, but they are more. They are not just social gatherings. They are that, but they are more. They are not just service projects. They are that, but they are more. Community Groups at Church of the Cross are small families of learning, serving missionaries where we learn to live everyday life with Gospel intentionality.
We don’t always succeed at this, but then again, life together is often messy. We’ve become convinced that when we look at community life in Scripture, there is more there than many of us have experienced. We want the kingdom to be tangible. We want you to learn to live in the sweet spot.