When we started on gathering in homes, it seemed so cool and radical to break out of the 1.5 hour service. It seemed so cool to take 3 or 4 hours, sharing, praying and eating. And the food, the meals, unbelivable, out of this world! Going to a service in a church seemed so gray and lifeless alongside what we experianceing. But After two years, what was a positive can also be a negative at times.
1. Because of the length of the gatherings, people are put off coming so regularaly and also put off loseing a whole Sunday when they have to host it.
2. It's been great to be participatry and we never want to lose it, but the problem is that alot of the time with everyone sharing it can drift, be shallow because of a lack of preperation and thought.
3. For the women (sounds sexist!) getting something decent prepared for the gathering has become a stress and a hassle, having to do it every Sunday.
I think one of the key answers is that 'Variety is the Spice of Life'. Anything no matter how amazing gets boring and stale without change and variety. In the end this happens when people show leadership, inititive and effort. If people stay on automatic pilot then the same thing happens week after week. In the end it takes inititive, planning, forward thinking and dare I say it some organisation to continually reinvent and bring creativity into this. Other then that I don't have answers at this time to these issues.
I just thought I'd reintroduce some thoughts here about 'Creative gatherings', I made mention in a previous comment that the Brethren had some strengths that may be relevant to your interests. Some of the problems you have mentioned (ie: catering, lack of preparation, length of service etc...) I believe can be addressed by building a fellowship 'culture'. I will talk a little about that later.
Before you can build a fellowship culture however, you have to have strong spiritual foundations. The strength of any later building work is determined by it. Spiritually speaking, the early Plymouth Brethren were inspired to return to a 1st century simplicity in worship, evangelism, and fellowship. The men and women had one goal in mind - Jesus Christ's imminent return and the completion of their role in his great commission. Their chief means in achieving this was a simple obedience to the Lords will as revealed through His scriptures. They had a very high view of the bible (both Old Testaments and New), and as such every member was expected to read and memorize them at length, daily, and to apply them personally as the Lord led. Their high view of the scriptures led them to affirm several key disciplines: Prayer, The Lords Supper, and Evangelism. (Fellowship was always important but it always grew out of the seedbed of these first 3 spiritual disciplines. Without that mindset I doubt that the Brethren movement would have amounted to much).
One thing that concerns me about some of the present house church movement is what appears to be a 'lack' of understanding of some of these 'basic' disciplines. We Westerners belong to an individualistic, narcissistic, rationalistic, 21st century culture, and it is only natural that elements of our secular world manifest themselves occasionally in our spiritual 'meetings' and fellowship. Attitudes such as: coming to 'get' in meetings instead of coming to 'give', a lack of personal preparation, an inability to commit to the 'fellowship of saints', the easy opting out of responsibilities in relationships. Servant-hood is a discipline that is countercultural and it is something that appears to be fading in Western Christianity. The quality of our fellowship is going to be determined by the quality of spirituality manifesting in our actions in serving the Lord and each other.
How do you build quality fellowship? As I remember back (to my early Brethren days) I believe there were several key areas: Time in each others houses, fellowship meals, working bees when members had needs. organizing both informal and formal small and large social events together (beaches, camps, sports, tramps, movies, going away together etc..) just getting to know new members by taking them home after the 'Lords Supper" was really important. Hospitality is perhaps the single most obvious and important attitude that comes to mind when I think about those early days. Those saints really knew how to make you feel welcome.
The best of the churches in my background were always very earthy, practical, pragmatic, and not 'super-spiritual'. They got on and did what ever was needed. If there were physical needs they met them. My mother was a solo mum and members used to come around and help her with gardening, carpentry etc...
As I look back on the strengths of those believers - the mature believers always seemed to have a pragmatic wisdom in serving the Lord. I am aware of other weaknesses in my church background, but these are some of the strengths and they may be relevant to what you and others are trying to 'build' in the quality of your home fellowships.
One other area that I thought I'd also briefly mention here is the format of your 'Meetings' when you do your 'spiritual stuff'. Try and keep it biblical - as in the 1 Corinthians 14 format. If everyone comes prepared beforehand it can be the most amazing opportunity for the Lord to input into our lives. Don't try to use these time to discuss too much, focus on the Lord, reflect on what is said and allow His Spirit to speak into each persons circumstances.
Just as a closing thought about the need to be countercultural in the world we live in. Gardens need careful preparation before planting, and they also need lots of tending. Whilst I believe in the 'organic' church, it doesn't just 'happen' out of nothing, we have to remember that any organic practices in gardening require preparation and lots of 'extra' work. However (as organic church members) we also choose not to lean upon the poisoning synthetic chemicals ('additions' to the gospel message from our church 'backgrounds') to 'maintain control' of our (spiritual) gardens. Be encouraged however that over the long term those organic practices we have chosen to use, will bring about a healthier crop of spiritual fruit, and therefore 'organic house church' I believe is ultimately the better way for the body of Christ to go. (even more importantly as we head towards the last days before Christs return).