When you suggest something like establishing a social calendar for the church and doing your best to attend the real-life events of your brothers and sisters as an act of fellowship and togetherness, the natural caution is: how do you prevent little cliques from forming?
It's not hard to imagine. You have a couple of persons who show up to someone's event, and then, they routinely show up to that person's event, and that person in turn shows up to their events and before you know it, there's a small group of maybe three or four persons or families who are doing just about everything together.
This isn't necessarily a bad thing; discipleship happens in smaller groups. The kind of fellowship that Jesus had with the disciples was just twelve men, and even within that, He had a core of about four (Peter, Andrew, James, and John...and sometimes, not even Andrew). There's no inherent problem with having very tight small groups of persons form through the social calendar type of fellowshipping.
AS LONG AS....
As long as they retain the heart of Jesus and don't shut others out who show up. As long as they don't become a closed group, you're okay. Remember that Jesus never pushed anyone away because He was busy with Peter, James, and John. He never failed to talk to someone in the crowd just because He was already talking to His disciples. So if you've got persons who are developing the heart of Jesus, as they should be if they are discipling together, then you don't really have to worry about cliques.
That requires, of course, that the persons in these smaller groups really are discipling one another and not just having fun together. It requires that they are forming the kinds of relationships where they can hold one another accountable, where they are pushing one another toward spiritual and relational growth, where they have their eyes constantly on looking for ways to put love into action - with one another and with the world around them. They can't just be hanging out because they happen to share common interests; the heart of every social fellowship has to be love for God and love for one another.
Now, a really cool thing also happens when you adopt a fellowshipping like this: bonds form that you might not have previously expected.
Sometimes, you end up with someone who has a passion for, say, tennis. And you find out that a kid in your church is playing on the local school's tennis team. That person with the passion starts showing up to support that kid - because they love tennis - and they end up loving the family.
Or you get someone whose past includes the tragic loss of a loved one too early to something like cancer, something that happened before they came to the church or that most of your church members don't know about them because they don't talk about it. But they see someone's biopsy appointment on the social calendar, and they show up in the waiting room. And that chance encounter becomes a friendship and a supportship that is healing for both of them.
Cool stuff just happens when you start to know one anothers' actual lives. When you start to engage in the place where you actually live. When you start to laugh and really, really do life together and not just a smattering of events on the official church calendar. It's such a cool thing to watch how God brings persons together in new and vibrant and exciting ways. It's amazing to watch how He grows them together through just showing up.
It's even cooler and more amazing to be part of it.