I think a combination of frequency and schedule would have a large impact. When I mean 'frequency', I'm not saying a gamenight every two days, it gets old and it's a bugger to organise. At the same time, one a month is no good because if somebody doesn't get invited, that's a month they have to wait. If I had to decide, I would probably either go for a couple a fortnight, it's something to look forward to and if you don't get on, you're not waiting an age. When I say schedule, I guess I really mean consistency. If everybody knows that Saturday night is gamenight then, and this is just me, it saves some hassle. It means I'm not checking back every five minutes to see if a date has been decided and it helps with working it into a daily routine. Will everybody be able to play it on one day? Definitely not. But by having fixed days and times, it helps. I could probably think of other things but those are the ones that come to mind at first thought.