Inviting people to "church" is a common way to think about and practice evangelism, at least in its initial stages. And it's okay as far as it goes, but I think in the missional church we need to re-think this emphasis.
Check out this image from Matt Stone's blog (from a post last year):

As Matt elucidates on his blog, the way we normally think of it is that the church service is the "way in," and from there we attempt to "assimilate" people into community life: cell groups, etc. Because of this our services have needed to be very accessible to "seekers" and the like. Again, this is okay as it goes, but there is very little impetus for anyone to go from that place into the deeper realms of community, and often we're left with churches that are a mile wide and an inch deep.
But what if it was the other way around? What if we thought of the church service as the "inner mysteries" of our faith, and the "way in" was through community events? The church service can then resume its traditional role as a formational practice for the Body of Christ: gathering not to attract outsiders, but simply to be formed as an authentic, missional expression of the gospel. Then the "way in" becomes the community that is engaged with the culture: small groups, parties, play-dates at the park, book clubs, brunches, "Alpha"-type classes, etc. From there, people can see a visible expression of what a gospel-shaped community looks like, and if they want to dive deeper, they can come to a worship service, where we are formed as a gospel-shaped people by gathering to adore God, hear his Word to us, respond in faith and prayer and obedience, receive his grace through the Eucharist, and be sent back out into culture with God's mission and love burning in our hearts.
This is what we have been experimenting with at Christ Community. Honestly it's a little frustrating because it is much slower work than simply waving a big flag and saying we have the coolest church service around. But it is good work, and we're starting to see fruit being borne in our community (more maturity), and amongst the culture our community inhabits (openness, inquisitiveness to the gospel). Slow and steady wins the race nowadays, it would seem. Pray for us!