In the XMPP community there are several regular meetings in different regions. Users, admins and developers meet there to exchange their experiences made with XMPP and instant messaging. This happens in the form of talks and general discussion in small groups. Compared to Sprints, Meetups are usually not used for developing XMPP software, but take place more frequently.
Meetups are mostly joined by local people, even though sometimes also people from far away come to visit. Thus, most meetups take place in large cities. Here you can find a list of meetups.