How about one community devoted to fun topics like showcasing strange or useful things people have used ARM processors for or things which have been noticed which might appeal to a chip designer but are not specifically ARM or fund raisers associated with ARM in some way? E.g. things like this video
Mechanical Turing Machine in Wood
or this educational game kickstarter
Turing Tumble: Gaming on a Mechanical Computer
they would of course just be a waste of time in a normal community but one needs a bit of diversion sometimes.