Small Groups have been around since the beginning and the groups do four things:
1) They devote themselves to the Apostles teaching.
2) They devote themselves to fellowship.
3) They devote themselves to the breaking of bread.
4) They devote themselves to prayer.
"You can certainly do more than pray, after you have prayed. But you cannot do more than pray, until you have prayed."
See the full notes here:
http://www.a.youversion.com/events/562579