Next week is OUCE in Southampton UK, where I'll be presenting on my recent work in time-series storage. I've never been to an OUCE, or Southampton, and I'm really looking forward to it.
Since you get to Southampton via London (from here), and since I haven't been back there in more than a year, I arranged to have a day or two there, and scored an opportunity to talk to the Cassandra London Meetup on Monday.
There is still time to sign up for OUCE, so if you're interested in OpenNMS talks and/or training, and can make your way to Southampton next week, consider doing so.
Unfortunately the meetup has a waiting list, but if you're in the London area and would like to chat Cassandra and/or OpenNMS over a pint, I'm your man.