Every Saturday in Appleton there is a tournament, but it's usually on-going and you can't just get into it. On the other hand, there are lots of people just hanging out that day, so I'm REALLY sure you can find an opponent. A friend of mine won some tournaments in Houston and New York with his Chaos Daemons, and he's there every Saturday and looking to play.
I'm there too, but my army isn't competitive enough yet. Maybe 2k points without enough railguns.
http://www.chimerahobby.com/