100state makes a great effort to promote and facilitate regional collaboration between the innovation and entrepreneurship communities of our region, including Madison and Milwaukee. A few things that our communities do:
Share event calendars
Sponsor bus trips to each other's notable events
Monthly twitter hangouts discussing relevant topics
Reciprocal community benefits (ex: shared membership between coworking facilities, meeting spaces, etc.)
The idea is to frequently create collisions between our communities to increase the probability of serendipitous moments.