One thing that we tried this year (to little success, I’m sorry to say) was to have a Friend Day. This is a day that’s planned well in advance so that you have time to talk to your friends, coworkers, neighbors, etc. about coming to church. The point of the service is to have a strong evangelistic message while going out of our way to make visitors feel welcome.
There are many different ways to do a Friend Day. One of them suggests the Pastor inviting someone from the local city with some degree of position (i.e. the Mayor, Police Chief, etc) and then showing the congregation a letter that the person will be attending. Then the Deacons would do the same.
Then there’s a more low-key way of doing it where you simply have people encourage others by stating that so-and-so is willing to come, you should ask your friends.
In the context of what we’ve been talking about, I would place the Friend Day as the last day of the Sunday School contest, and encourage people to invite their friends to the final Sunday. This would allow you to use the excitement from the VBS style Sunday School, the children that you’ve brought all the way from the Good News Clubs all the way here, and the adults that are both members and visitors into getting new people to come. The more people that you have attending, the more people they know and that they can invite.
Again, I would keep the worship service the same, with an emphasis on presenting the Gospel, and maybe conclude with an invitation. There could be an evangelism conference held after this, or something to keep the momentum going, but this would be the last stage of a planned course of events to bring people in.
At this point, the new people would have heard the Gospel and the basics of Scripture presented in multiple different venues, they would be familiar with the building and the people, and they would have been there on Sunday. This would break down the wall between the outsider and the member, and teach members to serve.
I believe that if there’s prayer and the Holy Spirit at work that the members of the church would be changed people throughout this process, and that it would have an effect from the nursery to the worship service itself. Nothing energizes a church like seeing souls saved and new members joining.