austin This reminded me of Browserquest by mozilla, where I haven't been able to connect in the past either
So I googled around a bit, a found this thread on avast forums with the same reports. It is also "officially" listed on this page as firewall issue. Strange thing is that I could fully play with this test, maybe it runs on a different port or something...
Then I checked a few settings on avast, and noticed that while the daily virus base was up to date, the program itself wasn't.
So I went from v6 to v7 and I now I can play with Browserquest and clay.io with avast enabled :]
Now a lot of people are probably still using v6 (it never noticed me of available updates...) or other listed antiviruses. Also I'm may end up using scoreoid (that I found in the meantime) for leaderboards.
I have a vague idea of what websockets really are, for realtime communication and such, but can you tell me why you're using them all over the place at clay.io, and if there's a benefit using them over "simple" ajax requests (e.g scoreoid) if I just need a basic leaderboard feature? (and considering they may be blocked by some random antivirus)