Back to Church Sunday is on September 28th, and is a chance to invite people back to church who've got out of the habit. Research on church leaving by Richter and Francis ('Gone for Good?') suggests that the two groups of people most likely to want to return to church are those who've stopped going because of 'life transitions' (e.g. they moved house), or because work and other commitments got in the way.
The BTCS website has various resources on it, and seems to have improved on last year. We're one of 35 or so churches in Bath and Wells Diocese who are doing it, and saw several new people coming along last year. The most effective thing was a personal invitation, rather than a leafletting blitz.
And of course this is only part of the picture. For the majority of those surveyed by Richter and Francis, church was part of the problem, not the solution, and they were pretty unlikely to return to church any time soon. This backs up what TEAR Fund discovered a last year, that the percentage of folk who might return to church is much smaller than what we thought. For some, returning to a church they never really meant to leave will be just the right thing. For many more, it is the church which has to move, in order to go to where people are.